Modern Masters sells a rust reactive paint. The primer is an acid blocking base which prevents the metal top coat from attacking the substrate. The top coat has iron particles in it. Once you apply that you spray it with the activator they sell. It's a salt etching solution. The iron particles rust in about 2 hours. You are supposed to apply the perma sealer over it. These don't look sealed. The iron particles continue to oxidize over time. Wouldn't want that getting in my eye. Super effect though.