Tung oil is a popular ﬁnish for wood projects. There’s just one problem with it—if you don’t use it all up, the leftover oil quickly turns rancid from air trapped inside the bottle. To keep it fresh, store the leftover oil in a collapsible plastic bottle ($7 at a photographic supply store). The accordion sides compress to drive out the air. If you have a little air left in the bottle when it’s collapsed, drop in some marbles to raise the oil level to the base of the bottle’s neck before tightening the lid.