I've been using the Mooncup for little over a year without any problems. During my last period, however, I left it in overnight and then some (due to a busy morning and a three-hour bus ride). When I finally had the chance to empty it, it did not smell nice. I decided to use pads for the rest of my period, boiled the cup like I usually do (five minutes) and thought little about it until my next period. The second time I emptied the cup this time around, the smell was back. I poked a sewing needle through the holes and washed it with warm water and dishwashing soap (the only thing at hand) before boiling it again, but it hasn't helped.
My fluid is usually fairly slimy and slow, but in both these cases, it was runny and looked slightly discolored. Because of this, I'm suspecting it is bacteria at work - particularly as the fluid has been normal after I stopped using the cup. However, the smell seems to originate from the outside of the cup, and boiling it did, as noted, not help.
So I'm basically asking for any input about what might be going on, and how I can fix it. I see that people suggest soaking the cup in water and vinegar, or using an sterilising solution. Unless anybody can tip me off about any German brands, the closest I have at hand is a dilution of this.