Urnex has a special formula to remove coffee oils and mineral deposits from brewers and vessels. The best way to see if your thermos needs cleaning is to use hot water, let it cool, then see if there is a taint of coffee or an off flavor. If so, you probably need some cleaning, even if there is no visible residue. 120 tablets per bottle. This will last you a long time.
We use Tabz to clean our office brewer on a regular basis - before it starts to make funky tasting coffee. For brewers, you can run a brew cycle with a Tabz tablet in the basket and simultaneously clean both the brew basket and carafe. You can clean the inside of additional servers (mugs, thermos bottles, carafes, airports, etc) with one TABZ™ per 64 oz (2L) hot water. Solution can also be used to wipe spray heads.
One bottle contains 120 4g tablets.
It contains a blue dye to insure proper rinsing after cleaning. The date on top of the jar is the date the jar left the factory, not an expiration date. Urnex states that Tabs will last for years if stored properly. Urnex also recommends to use Tabz on non-aluminum surfaces as alkaline detergents such as theirs are not generally compatible with aluminum.