Ohmigosh! I love the CO₂ tip. Before, when I've needed to create a low-oxygen environment (usually for the purpose of long-term food storage), I've either popped in one of those oxygen absorber packets or used dry ice. Only one problem: sourcing either one takes a bit of a song-and-dance.

But the baking soda and vinegar trick? Nifty and ultra-convenient. Will have to use that one next time.