Thanks, everyone, for your input. I've made progress. I washed it with acetone & wiped the residue off, followed by sanding with 60 grit paper until there's no discoloration left on the hull panels. Before I glass them, I'll sand a bit more with a finer paper so that the cleaned area is as smooth as the uncontaminated part of the panel. He'd managed to contaminate 8 different panels to varying degrees... both sides on some. Two panels had most of the resin -- on both ends, on both sides... others just had spotches in varying places. I haven't tried glass taping them yet, but when I do, I'll do one to see if it turns out okay before I do the rest.