Several reviewers also recommend this for stainless steel coffee pots! All you have to do is fill your bottle with warm water, drop a single tablet in, and let it fizz the gunk away. The tablet dissolves completely, so once you dump out the water, you can use your bottle again right away! Check out BuzzFeed's full write-up on Bottle Bright.
Promising review: "Can I give Bottle Bright 10 stars? This is a MIRACLE product. I saw it on Shark Tank last week and was really surprised that Lori was the only one that made them an offer (the other Sharks must not use Contigo travel mugs). I immediately ordered it to try and save my Contigo mug that I thought was too far gone. One 10 minute go-round with this product in warm water cleaned the dark brown layer of crud off the bottom of the mug, revealing perfect, shiny, good-as-new stainless steel underneath! I'd tried everything to get that off, but the shape of the bottle made it nearly impossible to scrub. With this product, it rinsed right off like it was nothing. I decided to try one more tablet with hot water and leave it overnight to get the stains off the sides of the bottle. This morning when I rinsed it out, I was absolutely blown away by how perfect it looks. I almost didn't want to put more coffee in it! Also, as the product was sitting and doing its thing in the water, there was no odor whatsoever, and there is absolutely no residual taste. I don't know how they did it, but this incredible product is a MUST-HAVE if you have a mug that you find impossible to clean!" —Erica C.
Get a pack of 12 tablets from Amazon for $8.