Amnesia scripting!! Removing item ONLY if in inventory?

[FlawlessHappiness]

I'd like to place a dagger in my map ("ceremony_knife"), but only for aesthetic purposes.. So I wanted to know if anybody knows a way to make the item not pickable, or, if it's not possible, to put a script that removes the knife from the inventory when you pick it up! Thank you very much and i hope my english is comprehensible!

Back to the first question:

Disabling interaction will not make it into a not-item. This means it will still have a blue glow around it.

What you can do it to back up the files, open it in the model editor, and make it an object instead of an item, in UserDefined Variables