Item duplication exploit/bug

Found a way to easily duplicate every item. anybody else seen this?

So that's how all those people got those impossible scores. Exploit-bert TD going strong! Until exploiting and cheating is punished in this game, this TD is nothing but a joke.

Exploits are always being worked on being removed from the game. After the next patch a good many of the current exploits will be patched out anyway. Andy can't find them all, that's why it's up to the community to find them and report them so they can be fixed.

How do you do it?