[MPWR]

I've been using Micro Sol for yearsnyears and have never come across a residue- but I have had another problem with it and SMS (specifically) decals. SMS CF is a metaillic colored film with the black pattern printed on top. Micro Sol is strong enough to soften and dissolve the black ink, and leave spots of it on the decal as it dries. If you read SMS's instructions, they are very specific about not leaving wet pools of Micro Sol to sit on the wet decal. I suspect this is related to the problem you're having. You can switch to a weaker decal solution (Micro Set is one), or follow SMS's instructions about not leaving solution to pool on the decals.