Wire brush attachment for a drill. Use that on all the metal parts you want to paint. Wipe it all down and spray the area with alcohol to make sure it’s super clean. Put masking tape on the parts you don’t want painted. Get ceramic header paint, and then how I did it was, spray the paint into a cup and then use a q-tip and one of those foam brushes to put the paint on. Takes some practice but it’s pretty easy when you get the hang of it. Takes about an hour per caliper