Whitening toothpaste isn't just for those pearly whites. As any tea or coffee drinker can attest, white mugs will undoubtedly get stained from frequent use. Cleaning them with dishwashing soap sometimes doesn't work too well, especially if you've left your morning cup sit in the sink too long. Keep a spare toothbrush around, a small squeeze of some whitening toothpaste, and give it a brush. The alumina in the toothpaste works as an abrasive and should remove the stains without too much trouble. Remember to rinse or your next cup might taste peculiar (at least you don't have to floss anything).