Coffee and tea stains in mugs are caused by tannins — natural compounds in tea and coffee that bond to ceramic and stainless surfaces and are resistant to regular dish soap. They build up over time into a brown film or ring that can look like a dirty mug even after washing.
Baking Soda Scrub (Best for Ceramic)
- Wet the inside of the stained mug
- Sprinkle 1–2 teaspoons of baking soda into the mug
- Use a damp cloth, sponge, or your finger to scrub the baking soda around the stained interior in circular motions — the mild abrasion lifts the tannin deposits without scratching ceramic
- Rinse thoroughly
- For stubborn stains, make a paste with baking soda and a little dish soap and let it sit for 5 minutes before scrubbing
Denture Tablet Soak
- Fill the mug with warm water and drop in one denture cleaning tablet
- Let soak for 30 minutes to 1 hour
- Swirl and pour out — most staining will be gone
- Rinse and wash normally
This is the easiest method for heavy staining and also works well for glass teapots and coffee carafes.
White Vinegar Soak
- Fill the mug with equal parts white vinegar and hot water
- Let soak for 10–15 minutes
- Scrub with a cloth and rinse
Stainless Steel Travel Mugs
Fill with warm water and 2 tablespoons of baking soda, shake, let sit 15 minutes, then rinse. For the lid and straw, use a small brush with the baking soda solution to scrub all crevices — travel mug lids trap tannin staining in their seals and gaskets.
Preventing Stains
- Rinse the mug with water immediately after finishing your drink — this prevents tannins from drying and bonding to the surface
- A quick baking soda scrub once a week prevents heavy build-up from developing