I carry two of these.
The first one:
1) Stores my aluminum alcohol stove in the pack so it doesn't get crushed.
2) Is used as a pee potty at night when I'm tenting. (The stove is stored in a ziplock bag inside the container. And I wash the container after use. No yuck factor, as far as I'm concerned. Its marked with a "P" so the containers don't don't get mixed up.)
3) Wash and rinse clothes.
The other one is used to:
1) Mix and drink protein powder drinks, electrolyte drinks and coffee.
2) As a bowl for hot food.
3) To store cooked food overnight (in the bear bag) if I can't finish it all.
4) During the day it rides near the top of my pack with that days snacks and drink powders inside. Works great to keep the Snickers bars from being crushed.
5) I've also used it to make egg or tuna salad, and to carry small amounts of fresh food that might otherwise leak into the pack.