It's most likely one of two things:
1) Residue from the MicroSet / MicroSol. I had that happen once and thanks to a hint from someone here it came off easily with a Q-Tip moistened with MicroSol.
2) If you used either acrylic paint or an acrylic clear coat, either the MicroSet, MicroSol, or water is causing the acrylic to fog. I haven't had this happen (and I use acrylics almost exclusively) but I have heard of it. I've read that another light coat of clear acrylic will sometimes clean it up.