If you are using createx paints, the alchohol may cause the paint to smear. Unless you are handling your plugs with hands that are very greasy, you should not have a problem with the clear coat. Problems come from not mixing the clear coat well enough, not applying it right, or applying it too soon after painting (solvents from the paint cause the clear coat to bubble). Probably other reasons too. I've never wiped a plug before clear coat. Well, once, thats how I found out the createx smears when it contacts alchohol
Jigman