I used the small discs made of scotch brite-like material that attach to a drill or Dremel tool. Taped it off and repainted with Eastwoods black rust encapsulator: lokks like new.
A hot air gun and one of my fathers wood carving chisels, shaped for cutting grooves to scrape off the adhesive. Followed this with some abrasive paper and some primer. Dad would turn in his grave if he could see me abusing his woodworking tools like that.
if you just want to remove the adhesive and not the paint get some 3M woodgrain and weatherstrip remover in a spray can. it works very well and doen't remove the paint. 3M also makes a disc designed to remove pinstriping other vinyl type graphics that works well and doesn't remove any paint