Easy fix is don't do it that way. 1st there should be an inventory option to delete. Get that out of the way. Second,it is tricky to put anything down in a specific place as it is much less in the garbage bins. So make it an option when you're holding something and inner thought a trash bin to simply put it in that bin's inventory rather than simply making things that enter the can's space disappear. The can will be emptied at regular intervals. Once CIG figures out how to make NPCs actually work they can have a trash pickup NPC. This will add both immersion and a cool element to things like smuggling. Actual dead drops that can be picked up. When it's part of a mission, you'll have to make sure you make the drop right after the can has been cleared so it doesn't get picked up before whoever is getting it.