I have been using the Micro-Set, Micro-Sol, and Future floor wax approach on decals for about 20 years with excellent results; however, I have recently encounted a new problem. I am building 1/350 scale submarine kits from Yankee Modelworks with a black and anti-fouling red color scheme and when applying the draft marks and other decals, I often get an unremoveable white stain where the decal solutions have settled on the finish. This is not silvering under the decal film, and it happens on both the black and red; although, it is more apparent on the black. Wiping up any excess liqiud immediately after application often precludes the problem but does not guarantee that the staining will not occur.
The problem has happened on more than one kit, and I have purchased new decal solutions and Future; however, this has not solved it.