If you're like most woodworkers, you've probably thrown out a fair amount of finish over the years because it skinned over, turned to gel, or hardened in the can. Oxygen stored along with leftover finish is what makes the product go bad. Bloxygen (adapted from the wine industry) lays down a blanket of heavier-than-air inert gas that blocks oxygen from reaching the finish, so even a product as sensitive as tung oil finish can last for years in a tightly sealed container. With a mixture of naturally occurring, non-toxic and non-flammable FDA grade nitrogen, argon & carbon dioxide, each can of Bloxygen will protect scores of cans of finish, from oils to paints, varnishes and stains--anything that cures with exposure to oxygen (this means water-based finishes don't need Bloxygen). Each can of Bloxygen contains 150 seconds' flow of gas; the manufacturer recommends a 2-second shot to exclude oxygen and preserve your finish.