diff --git a/apps/openmw/mwclass/apparatus.cpp b/apps/openmw/mwclass/apparatus.cpp
index 323ebfa63c..878c9f59ec 100644
--- a/apps/openmw/mwclass/apparatus.cpp
+++ b/apps/openmw/mwclass/apparatus.cpp
@@ -144,7 +144,7 @@ namespace MWClass
         return MWWorld::Ptr(cell.insert(ref), &cell);
     }
 
-    bool Apparatus::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Apparatus::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Apparatus) != 0;
     }
diff --git a/apps/openmw/mwclass/apparatus.hpp b/apps/openmw/mwclass/apparatus.hpp
index 82dff46ffb..c5066d0fcb 100644
--- a/apps/openmw/mwclass/apparatus.hpp
+++ b/apps/openmw/mwclass/apparatus.hpp
@@ -60,7 +60,7 @@ namespace MWClass
 
             virtual std::string getModel(const MWWorld::ConstPtr &ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
 }
 
diff --git a/apps/openmw/mwclass/armor.cpp b/apps/openmw/mwclass/armor.cpp
index f575f99557..0554c738e3 100644
--- a/apps/openmw/mwclass/armor.cpp
+++ b/apps/openmw/mwclass/armor.cpp
@@ -382,7 +382,7 @@ namespace MWClass
         return ref->mBase->mData.mEnchant;
     }
 
-    bool Armor::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Armor::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Armor)
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
diff --git a/apps/openmw/mwclass/armor.hpp b/apps/openmw/mwclass/armor.hpp
index b5ec114456..4fd426da4d 100644
--- a/apps/openmw/mwclass/armor.hpp
+++ b/apps/openmw/mwclass/armor.hpp
@@ -85,7 +85,7 @@ namespace MWClass
 
             virtual int getEnchantmentPoints (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
             /// Get the effective armor rating, factoring in the actor's skills, for the given armor.
             virtual int getEffectiveArmorRating(const MWWorld::ConstPtr& armor, const MWWorld::Ptr& actor) const;
diff --git a/apps/openmw/mwclass/book.cpp b/apps/openmw/mwclass/book.cpp
index d4e67fdbe7..9ef9b769e2 100644
--- a/apps/openmw/mwclass/book.cpp
+++ b/apps/openmw/mwclass/book.cpp
@@ -190,7 +190,7 @@ namespace MWClass
         return ref->mBase->mData.mEnchant;
     }
 
-    bool Book::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Book::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Books)
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
diff --git a/apps/openmw/mwclass/book.hpp b/apps/openmw/mwclass/book.hpp
index b70b3b5f55..21c9a018de 100644
--- a/apps/openmw/mwclass/book.hpp
+++ b/apps/openmw/mwclass/book.hpp
@@ -66,7 +66,7 @@ namespace MWClass
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
 }
 
diff --git a/apps/openmw/mwclass/clothing.cpp b/apps/openmw/mwclass/clothing.cpp
index 1316fabd2b..f5000229b1 100644
--- a/apps/openmw/mwclass/clothing.cpp
+++ b/apps/openmw/mwclass/clothing.cpp
@@ -278,7 +278,7 @@ namespace MWClass
         return ref->mBase->mData.mEnchant;
     }
 
-    bool Clothing::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Clothing::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Clothing)
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
diff --git a/apps/openmw/mwclass/clothing.hpp b/apps/openmw/mwclass/clothing.hpp
index 3ad0b12f9a..4c0240e746 100644
--- a/apps/openmw/mwclass/clothing.hpp
+++ b/apps/openmw/mwclass/clothing.hpp
@@ -79,7 +79,7 @@ namespace MWClass
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
 }
 
diff --git a/apps/openmw/mwclass/ingredient.cpp b/apps/openmw/mwclass/ingredient.cpp
index 3a2cdfc159..5c2cabd4ce 100644
--- a/apps/openmw/mwclass/ingredient.cpp
+++ b/apps/openmw/mwclass/ingredient.cpp
@@ -181,7 +181,7 @@ namespace MWClass
         return MWWorld::Ptr(cell.insert(ref), &cell);
     }
 
-    bool Ingredient::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Ingredient::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Ingredients) != 0;
     }
diff --git a/apps/openmw/mwclass/ingredient.hpp b/apps/openmw/mwclass/ingredient.hpp
index 309917c44a..dddf538d19 100644
--- a/apps/openmw/mwclass/ingredient.hpp
+++ b/apps/openmw/mwclass/ingredient.hpp
@@ -59,7 +59,7 @@ namespace MWClass
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
 }
 
diff --git a/apps/openmw/mwclass/light.cpp b/apps/openmw/mwclass/light.cpp
index fc3f4e5c56..46ddeeb5f3 100644
--- a/apps/openmw/mwclass/light.cpp
+++ b/apps/openmw/mwclass/light.cpp
@@ -213,7 +213,7 @@ namespace MWClass
         return MWWorld::Ptr(cell.insert(ref), &cell);
     }
 
-    bool Light::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Light::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Lights) != 0;
     }
diff --git a/apps/openmw/mwclass/light.hpp b/apps/openmw/mwclass/light.hpp
index 68529e2d0f..f0061117b9 100644
--- a/apps/openmw/mwclass/light.hpp
+++ b/apps/openmw/mwclass/light.hpp
@@ -69,7 +69,7 @@ namespace MWClass
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
             std::pair<int, std::string> canBeEquipped(const MWWorld::Ptr &ptr, const MWWorld::Ptr &npc) const;
 
diff --git a/apps/openmw/mwclass/lockpick.cpp b/apps/openmw/mwclass/lockpick.cpp
index d26585ed3b..26f7fba10e 100644
--- a/apps/openmw/mwclass/lockpick.cpp
+++ b/apps/openmw/mwclass/lockpick.cpp
@@ -162,7 +162,7 @@ namespace MWClass
         return MWWorld::Ptr(cell.insert(ref), &cell);
     }
 
-    bool Lockpick::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Lockpick::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Picks) != 0;
     }
diff --git a/apps/openmw/mwclass/lockpick.hpp b/apps/openmw/mwclass/lockpick.hpp
index fa24c0c004..e06060172b 100644
--- a/apps/openmw/mwclass/lockpick.hpp
+++ b/apps/openmw/mwclass/lockpick.hpp
@@ -61,7 +61,7 @@ namespace MWClass
 
             virtual std::string getModel(const MWWorld::ConstPtr &ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
diff --git a/apps/openmw/mwclass/misc.cpp b/apps/openmw/mwclass/misc.cpp
index a29142f07c..aba92ae3dc 100644
--- a/apps/openmw/mwclass/misc.cpp
+++ b/apps/openmw/mwclass/misc.cpp
@@ -228,10 +228,9 @@ namespace MWClass
             return boost::shared_ptr<MWWorld::Action>(new MWWorld::ActionSoulgem(ptr));
     }
 
-    bool Miscellaneous::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Miscellaneous::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
-        MWWorld::LiveCellRef<ESM::Miscellaneous> *ref =
-            item.get<ESM::Miscellaneous>();
+        const MWWorld::LiveCellRef<ESM::Miscellaneous> *ref = item.get<ESM::Miscellaneous>();
 
         return !ref->mBase->mData.mIsKey && (npcServices & ESM::NPC::Misc) && !isGold(item);
     }
diff --git a/apps/openmw/mwclass/misc.hpp b/apps/openmw/mwclass/misc.hpp
index 9583ce2dac..bc15f2c5f3 100644
--- a/apps/openmw/mwclass/misc.hpp
+++ b/apps/openmw/mwclass/misc.hpp
@@ -59,7 +59,7 @@ namespace MWClass
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
             virtual bool isKey (const MWWorld::ConstPtr &ptr) const;
 
diff --git a/apps/openmw/mwclass/potion.cpp b/apps/openmw/mwclass/potion.cpp
index cf83089d22..8ca8e51114 100644
--- a/apps/openmw/mwclass/potion.cpp
+++ b/apps/openmw/mwclass/potion.cpp
@@ -175,7 +175,7 @@ namespace MWClass
         return MWWorld::Ptr(cell.insert(ref), &cell);
     }
 
-    bool Potion::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Potion::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Potions) != 0;
     }
diff --git a/apps/openmw/mwclass/potion.hpp b/apps/openmw/mwclass/potion.hpp
index e0cc2722b8..c4e9dba3d6 100644
--- a/apps/openmw/mwclass/potion.hpp
+++ b/apps/openmw/mwclass/potion.hpp
@@ -58,7 +58,7 @@ namespace MWClass
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
 }
 
diff --git a/apps/openmw/mwclass/probe.cpp b/apps/openmw/mwclass/probe.cpp
index 53403e10a7..89b7f0ab58 100644
--- a/apps/openmw/mwclass/probe.cpp
+++ b/apps/openmw/mwclass/probe.cpp
@@ -162,7 +162,7 @@ namespace MWClass
         return MWWorld::Ptr(cell.insert(ref), &cell);
     }
 
-    bool Probe::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Probe::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Probes) != 0;
     }
diff --git a/apps/openmw/mwclass/probe.hpp b/apps/openmw/mwclass/probe.hpp
index fccb94ebbc..79f1831b3b 100644
--- a/apps/openmw/mwclass/probe.hpp
+++ b/apps/openmw/mwclass/probe.hpp
@@ -61,7 +61,7 @@ namespace MWClass
 
             virtual std::string getModel(const MWWorld::ConstPtr &ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
diff --git a/apps/openmw/mwclass/repair.cpp b/apps/openmw/mwclass/repair.cpp
index 5e8cbad538..3e6bcca950 100644
--- a/apps/openmw/mwclass/repair.cpp
+++ b/apps/openmw/mwclass/repair.cpp
@@ -161,7 +161,7 @@ namespace MWClass
         return boost::shared_ptr<MWWorld::Action>(new MWWorld::ActionRepair(ptr));
     }
 
-    bool Repair::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Repair::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::RepairItem) != 0;
     }
diff --git a/apps/openmw/mwclass/repair.hpp b/apps/openmw/mwclass/repair.hpp
index 06ccf8c35d..0e9c21cdb8 100644
--- a/apps/openmw/mwclass/repair.hpp
+++ b/apps/openmw/mwclass/repair.hpp
@@ -67,7 +67,7 @@ namespace MWClass
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
 }
 
diff --git a/apps/openmw/mwclass/weapon.cpp b/apps/openmw/mwclass/weapon.cpp
index d8aac64e46..3a827088ce 100644
--- a/apps/openmw/mwclass/weapon.cpp
+++ b/apps/openmw/mwclass/weapon.cpp
@@ -419,7 +419,7 @@ namespace MWClass
         return ref->mBase->mData.mEnchant;
     }
 
-    bool Weapon::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Weapon::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return (npcServices & ESM::NPC::Weapon)
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
diff --git a/apps/openmw/mwclass/weapon.hpp b/apps/openmw/mwclass/weapon.hpp
index 556f92e0b5..29222bb5dd 100644
--- a/apps/openmw/mwclass/weapon.hpp
+++ b/apps/openmw/mwclass/weapon.hpp
@@ -81,7 +81,7 @@ namespace MWClass
 
             virtual std::string getModel(const MWWorld::ConstPtr &ptr) const;
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
             virtual float getWeight (const MWWorld::Ptr& ptr) const;
 
diff --git a/apps/openmw/mwworld/class.cpp b/apps/openmw/mwworld/class.cpp
index 7f6006c5cd..9111215d2b 100644
--- a/apps/openmw/mwworld/class.cpp
+++ b/apps/openmw/mwworld/class.cpp
@@ -55,7 +55,7 @@ namespace MWWorld
         throw std::runtime_error ("class does not represent an actor");
     }
 
-    bool Class::canSell (const MWWorld::Ptr& item, int npcServices) const
+    bool Class::canSell (const MWWorld::ConstPtr& item, int npcServices) const
     {
         return false;
     }
diff --git a/apps/openmw/mwworld/class.hpp b/apps/openmw/mwworld/class.hpp
index f12b90ecac..8d64f9cbe4 100644
--- a/apps/openmw/mwworld/class.hpp
+++ b/apps/openmw/mwworld/class.hpp
@@ -261,7 +261,7 @@ namespace MWWorld
             virtual void adjustScale(const MWWorld::Ptr& ptr, osg::Vec3f& scale, bool rendering) const;
             /// @param rendering Indicates if the scale to adjust is for the rendering mesh, or for the collision mesh
 
-            virtual bool canSell (const MWWorld::Ptr& item, int npcServices) const;
+            virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
             ///< Determine whether or not \a item can be sold to an npc with the given \a npcServices
 
             virtual int getServices (const MWWorld::Ptr& actor) const;