Here's a demo map of the system you want:
View attachment Item Removal system.w3x
I tried to make it as simple as possible but since there's many way an item can be dropped, I had to made a few triggers..
For instance, the system recognize all these situations:
-Item dropped by a unit/Hero from their inventory
-Item dropped after a unit dies (loot)
-Item dropped after a destructible dies
-Item created via triggers.
Furthermore, the system can interrupt the expiration time. For example: An item is dropped in X area, and after 7 seconds, the item is picked up and dropped elsewhere; well it won't be removed 3 seconds after being pick-up. It will be removed 10 seconds after being re-dropped (if it's in a region where items are removed). Although, if the item is kept in the inventory, it won't be removed at all.
As you can see, the system is quite complex since I tried to figure every possibilities.
I hope it works like you wanted to, tell me if anything's wrong.
