I've been using the same autocross magnets for a few years with no problems on my black Z28. Today, however, I go to remove the rectangular magnets after the fun and notice a an outline of the magnet and splotches all throughout the center where the magnet was placed . It's looks as if the magnet broke down and had some chemical reaction on the paint. i washed and clayed the area a few times. It looks a bit better, but it is still very obvious when in direct light. I'm wondering what else to try to try an fix this. I did a search and didn't really see anyone that's had this. I can post a pic a bit later. Thanks a bunch!

 

I just found the issue and solution if anyone has this. If there is any moisture between the magnet and paint (lots of rain today), an ugly imprint will be left behind. Washing, claying, cussing won't do the trick and it looks very bad. A light polish (Zaino Z5, Meguiars ultimate polish) however applied with moderate pressure will remove.