What can be used to remove epoxy that spilled onto a tile floor and hardened?

Answer 1

try slipping a razor blade under the edge and pry itoff. When set, as long as the tile isn't really porous, the epoxy should pop off completely
Good luck

Answer 2

If it's ceramic or quarry tile you might try a rag wet with acetone. If the spill is thick, it could take a long time to soften it up, if it works at all. Just try to keep the rag wet and ventilate the area well. Not much " gets to " epoxy. g.l.