I have a DivaCup that's about two to three years old, and it got some serious stains going so I soaked it in 3% hydrogen peroxide overnight. It removed the stains like a charm--the thing looked like new. I wore it once as a dry run (to the gym), washed it with unscented soap as I usually do, and put it away. Today, I started my period. I popped the cup in, and all was fine until I removed the cup to empty it out. The most horrific cheesy stench met my nose. I was so shocked I actually thought my dog farted. My dog was so shocked she came in from the other room. Yeah, it was like a good French cheese.
Anyway, I washed the cup with soap, then boiled it for about 20 minutes. It still smells. I think the thing that DivaCup's webpage warns against has happened: the peroxide deteriorated the silicone. Soaping the cup after my dry gym run didn't get all the vaginal ladygerms out. The cup is basically ruined now, too--I don't think I want to risk putting it back in. I don't want to get BV or a yeast infection in the middle of my period. The plan is to use pads for the rest of it, and it's a lucky thing I have another cup on the way (ordered two Yuukis; too bad they are taking forever to get here). Ugh, I hate pads.
So I am not really asking for help--this might be more in the vein of a cautionary tale. But I'm curious--do those of you who have experienced the stinky cup phenomenon use peroxide or any other non-recommended methods on your cup?