I always waterproof my USGS topo maps with Thompson WaterSeal. Bought a new can and....did they change the formulation or something? Used to be clear and now it's a milky consistency. Seemed to coat my maps okay, but the paper was really flimsy--was worried I was going to tear it. (I hang it on wires in my garage to dry it.) Maybe USGS got cheap on the paper or something.
