: Unfortunately, you can't just wipe it away with a damp cloth. I wet
: sand the surface and wipe it up with an old T-shirt or use a
: scotch bright pad and use that with a little detergent and
: water. You need to scrub it good and wipe up the water with a
: clean cloth or paper towels. A sponge just ends up pushing the
: blush around. What you describe is a classic blush problem.

Okay, thanks for your input everybody. Lots of good tips here. I'm not sure if the cratering was due to blush, or to oil contamination from the air compressor, or possibly even from the bucket I had the water in when I was wiping it. All good hypotheses. In any case, I'll use the vacuum next time to clean it, as well as scrapers instead of sanding. I'll watch for blush, and clean it properly if necessary. For getting good even coats, I'll use squeegees and rollers, set it as thin as possible, and use medium or fast-set epoxies to speed up the hardening process. (Also I'll keep the shop and epoxy warm-- my basement isn't cold, but it ain't exactly warm, either...)

Now I want to finish this train-wreck so I can start over on a NEW boat!! :)