Does anyone use biological (laundry) washing powder (Sometimes just called 'Bio') to rid their cup of stains? I use a bio washing powder, like Persil, for my clothes, but also to clean my bath occasionally, because it has enzymes which break down organic matter such as skin, sweat, and also blood. So today I thought I might give it a go with my (uk) Mooncup, which had become very stained, and it's come out like new! I just put a teaspoon of powder into a cup of warm water, submerged the Mooncup for 20 minutes or so, and when I dried it off all the stains had disappeared, even the hard-to-get ones like those in between the lettering that says 'Mooncup' inside the rim. This is by far the easiest way of cleaning my cup that I've discovered.