So there I was, free diving in a pond when I found something covered with muck that got my attention. It turns out it was a U.S. Divers Technisub mask (a tri-vision model called the Corsica) and an Impulse snorkel. It appeared like it hadn't been marooned in the water for all that long, but it still had a lot of algae growth. The mask is in pretty good shape, and is a clear silicon unit so I have a question: what's the best way to really clean this sucker up? It might make a decent backup mask. I have used soap and water so far, but I'm wondering if there isn't a better way to really get the pond off of this unit.