I had previously modified and painted my horn cover. Knowing I'm going to paint my tank soon, I wanted my horn cover and rear fender (what's left of it) to match.
I picked up some 3M Scotch-Brite Paint & Rust Stripping discs that fit in a handheld drill. They work great! Here's the paint stripping in progress on the horn cover.
I was able to strip the paint off the outward-facing portion easily. I just roughed up the back as that was much more difficult to remove. Then I primed it with a few coats of Duplicolor self etching primer.