If you sell a negative amount of anything (up to -9999) at a shop you get that amount back plus the cash that amout would have sold for.
I've tested this backwards and forwards and its always duplicable with any item.
I found this too not long ago along with some other bugs. I have pm-ed schema about it.
Edit: from my testing it seems that it only works if you have one of the item already.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
