I want to rust the iron. I will make an incision and soak it with salt water. When I move on, you need to agitate the iron with the magnets until all of it is rusted.

[ She wipes the blade of a knife down with the alcohol. Even the cloth she uses glancing against the blade leaves a long cut in it - she's been making sure to sharpen the thing the the point where it's so sharp that the incision, at least, won't cause any pain. the rest, she can do little about. ]

Some of the iron will be pulled out by the magnets. What can't be will be made useless by the rusting. I don't think your mother would care much for the idea of rust in the body, but it's- better, at least.