Why Your Coffee Mugs Have Stubborn Stains And How To Get Rid Of Them

Your view of coffee mug stains — like that other famous glassware optimism metric — is also a litmus test for your view on life. Sure, maybe your favorite daily coffee or tea cup is tarnished. But maybe, instead, it's half pristine. Pollyanna nonsense aside, you bought your coffee mugs to look and perform a certain way, and there are enough supposed household hacks to keep them like new that you might as well give them a try.

Even when glazed, coffee and tea cups can develop hairline cracks, chips, or worse that expose the porous porcelain beneath. Those unvarnished areas will more easily soak up the tannins that help give coffee and tea their rich color (similar to the tannins that impact your wine). That's why these stains don't typically present with uniform saturation. And, because they're essentially dyed in, neither soapy water nor a run through the dishwasher will be an effective remedy. But lemon juice, toothpaste, white vinegar, and baking soda paste are all said to be solutions. So we tried each. We had, shockingly, only one such vessel imbued with the hues of morning bevvies past in our kitchen cabinets. A mint-colored mug shaped like the kind you'd find in a diner was lined inside with thin mahogany rings. The rest of our collection unaffected, we had a very limited surface area to test four common stain-lifting compounds all at once: baking soda paste, toothpaste, lemon juice, and white vinegar. Literally do not run this simultaneous test at home.

To keep each compound — the lemon juice, toothpaste, white vinegar, and baking soda — as separate as possible and to better identify their individual stain-removing abilities, we conceptually divided the discolored mug into quadrants. Then we applied about a quarter-sized amount of toothpaste and baking soda paste to opposite sides, and covered each with clear packing tape to keep them from running. Because the white vinegar and lemon juice were totally liquid, we soaked a cotton ball with each and taped those to the cup's two remaining sections in an effort to keep contact with the stains. An hour later, we removed everything, ran the mug under hot tap water, and wiped it out with a clean kitchen sponge. The results were unexpected.

The mug, which had been run through the dishwasher on regular rotation who knows how many times, stains remaining, was now completely clean. The tape had more or less done its job of keeping each property separate, but some had seeped out. Still, if any one of these four common cleaning agents — the toothpaste, white vinegar, baking soda, and the always versatile lemon juice — had been ineffective, at least a small area of staining would have remained. Instead, the mug is now back to its factory setting. So, the next time you feel like those cups are half tarnished, give them a good coat of whichever item you've got lying around. It might not polish your worldview, but it'll be one little task, complete.