Fan a hand-held torch over them right on the Jeep, just don't stop in one place. In less than 10 minutes, I had mine looking new without even taking them off. No masking, no paint, chemicals, fluids... Done. And it doesn't wash off.
I intend to live forever. So far, so good.
'99 Wrangler Sport: 2.5" Old Man Emo lift and shocks, adjustable trackbars, Quick-Disko sway links, rollin on 31" BFG A/Ts