Black Contigo AUTOSEAL Stainless Steel Vacuum Insulated Tumbler

Denture tablets. I rinse the lid asap, then once a week or so I fill the lid with water and drop in a tablet. Fresh and not minty afterwards.

Nevermind... just got this mug yesterday. The included cleaning instructions CLEARLY state to wash-out the lid immediately after you're done using the mug.

So I guess my original suggestion was correct. Wash the mug as soon as you can, don't leave it sitting around & it should be fine.

@Emily... I'm curious if you experienced the "coffee gunk" issue with just plain black coffee or mostly when using coffee that had creamer & sugar added to it?

I can see how the sugar & cream could gunk things up over time, but was wondering if those who drink only black coffee are also experiencing this.

Guess you could always immediately rinse the mug & lid as soon as you're done using the mug (providing you have easy access to a nearby sink/washroom) in order to prevent build-up.

I have had 2 of these mugs. They really do keep your coffee hot for a long time and they will not leak. However, they are a BEAR to clean. The lid has many nooks and crannies and coffee "gunks up" in there easily and is very very hard to remove. I have tried hot hot water, dishwasher, bleach, various assortment of little brushes, you name it. It's a lot of work to keep the lid clean and I'm not really sure it's worth it.

I use a Contigo as well; works great.