How to get rid of Winry Rockbell in a few easy steps.
First of all you need to sneak into her house, and not be caught by them or Den.
Find her favorite tool which is the wrench, pocket it and replace it with a rubber wrench. (It looks the same and weighs the same).
Get out of the house and quick and quite to not get noticed.
Peek in thru the window, and watch what unfolds.
Winry will walk into her shop looking for her wrench, and start to work on some auto mail. She tries to use the fake wrench, but it only squeaks when she turns it.
Winry: "What the hell, where's my real wrench"
She runs through her whole shop throwing the tools and junk into a pile, searching for her favorite wrench.
Winry: "Where the hell is it, once I find out who took it I will kill them".
She turns around thinking she found her wrench, but it's at the bottom of the pile. She pulls it out not thinking what will fall on her, only thinking of her wrench. The pile starts to shake, then wobble, and finally falling and crushing Winry like a pancake.