Cup cleaning?

I’ve been using a blossom cup for a couple months and LOVING it. I’m now wondering what people do to keep it clean?

I wash it with “diva cup” wash each time I canceled it at home, and just rinse with water when I have to change it elsewhere. I also have been trying to boil it after my period finishes before storing it away for the next month. Is this enough to keep it sanitary?

Is it possible to keep it totally clean without the boiling? Sometimes it’s hard to find time to boil it when my BF is out (we live together) and while I’m sure it wouldn’t be a problem, I don’t want him to have to see me boiling it with a pot we otherwise use to cook with.

Finally, my originally blue cup is now a eww-looking brown color, even after washing. I know that it’s not actually a problem, but has anyone had luck either removing or preventing stains?

Thanks!