Help! Menstrual cup users!

My cup developed this horrifying stench after I accidentally went 24 hours without emptying it. I know, bad idea. But I was sick and kinda forgot. I've tried everything I can think of to get rid of the stink (peroxide, rubbing alcohol, boiling, washing, essential oils, sunning, etc.) and the smell does go away. However, it comes back every time I use the cup. I should probably note that my actual vagina smells fine. Is there anything I can do to permanently remove the stink from my cup, or is it time to just chuck it and get a new one?