I used 10 of the purple clean n strip discs to completely strip several layers of desert baked on paint from my 67 chevelle. I used the 4.5 inch ones that go on an angle grinder. They may be pricy, but work excellent without warping the metal or digging into the metal like a DA will. Also no worries of chemicals seeping back out later down the road. (unlikely but it does happen) They did strip it somewhat smooth, so I scuffed the bare surface a little before shooting SPI's epoxy primer on my car. Here they are on 3m's site. Havent tried the Roloc ones, so I cant comment on that. I stripped the jams and such with a cheapo sandblaster.
http://www.shop3m.com/61500187564.html