Personally I use my DivaWash, which is the soap that's made specifically to clean Diva Cup brand menstrual cups. It's designed to clean medical grade silicone after prolonged insertion in the vagina and is pH balanced. I happen to have it on hand and it seems like the perfect agent for me. A little pricey, though, if you're getting it just to clean toys. You can get it pretty conveniently at Whole Foods.