How long has the u-coat been on there? If it is fresh, some mineral spirits(varsol/naptha) on a rag should get it off. It's gonna take a while to do it, tho, no matter how you do it.
When I took the u-coat off my '74, I spent about a month crawling around under it with a razor blade, carefully peeling the stuff off. I just did the underbody and chassis, and left it on the wheel-wells.
When they did it at the factory, some undercoating did get sprayed on the storage wells, and the spare tire carrier, but it wasn't supposed to....they were just usually in a hurry. This was done before the body drop, so there would have been no u-coating on the frame, or other chassis parts.
Hope you can get most of it taken off easily. One thing you need to check is if ANY got on the driveshaft, or the halfshafts....that's a definite NO-NO!
Adams' Apple2010-12-10 20:27:49______________
Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"