The magnets seem pretty strong but as you can see from the photo I don't put anything heavy on them so YMMV. I hated the stickers so I soaked them in warm water and dish soap and got to work with the brush. I then did all the leftovers with slime and cleaned with acetone. After that I applied several coats of clear coat as I don't know what those magnets are and I suspect they can attract rust. I'm in an arid climate in California so I'm not worried. Overall I'm disappointed with these stickers given the price and the fact that I had to make an extra effort to remove them, but in the end they worked for what I needed them for.