I think you got me wrong. GameInstance thingy is OK. I meant what should I do instead of Destroy() to have the items picked up stay there. For example I have seen some tutorials on inventorie using a DataTable, basically they enter all he properties an item can take including an ID number and make a list of all items in the game. Then they were just calling that ID number to create/ drop/ pick up items real time (kinda like The Elder Scrolls game style I suppose ?) But that seemed strange to me so I choose this way.
For example is there a function I can use instead of Destroy() in UE4 for these type of situations or something ? Or maybe I can implement a function called DisablePickedUpItem() that sets CanTick, PhysicalCollision or all other things to false ?
Also sorry I am new to this inventory thing. If I don’t sound sensible please go easy on me 
Thanks.