My topos are all painted with mapseal. Application must be done with care. The applicator is a bottletop brush. The topos became fragile very quickly until thoroughly dry. a formica or glass surface is a must to reduce sticking. I haven't tried any dunk tests as yet. Topos @ $7 ( and my compulsive collection for places I haven't been to yet) make me err to caution and carry a map case.