Tricks of the Trade: Painter

Tricks of the Trade is entertaining, but really should steer clear of “scientific” explanations. “Before resealing a can of paint, blow one deep breath into the can and close it quickly. You’ll fill it with carbon dioxide, which will keep the paint from oxidizing.” Sorry, but no: we don’t breathe out pure carbon dioxide. Exhaled air still contains relatively little carbon dioxide (4%, vs 0.04% in inhaled air) and plenty of oxygen (17%, vs 21% in inhaled air) (source).