you only need to clean/rinse it, you don't need to sterilise it, you wouldn't sterilise fingers/a penis!:)

you can just use water or any mild soap, I use johnson's baby shampoo because it's easy to squeeze into the cup.

you could put the cup in an old mug/tupperware, pour boiling water from the kettle etc and leave for 10 mins if that makes you feel better.

you could soak in in white vinegar or scrub baking soda and water into a paste with an old toothbrush, but those are more for stain removal, you don't need to do anything except rinse in water.

Plain old soap and water! Be sure to rinse all the soap residue off your cup and your hands before they touch your delicate parts.

"As clean as cutlery." How clean does a fork have to be for you to put it into your mouth? Use the same guidelines for your cup.

I don't have a Yuuki, but with my silicone cup I've tried boiling it a few times, airing it out in the sun (mostly to lighten up stains), white vinegar scrub and diluted hydrogen peroxide (again, for stains). All work fine, but ultimately I feel that my cup is clean enougn to wear when it's been washed and rinsed. I mostly use a feminine wash that I used to use on my parts, but now it's just for cups. Ideally something that doesn't leave a moisturizer, anti-bacterial film, conservatives or perfume behind.

I only use soap before I start to wear my yuuki and after I'm done. I generally don't sterilize it with anything else. I use just water inbetween uses.

Because of the length of times cups are in, I personally feel better boiling mine. I've had a yeast infection issue while wearing a cup, no definite causation though. Obviously no cup will stay sterile and it doesn't need to be to be used, but I prefer to boil after use for the next cycle. I hydrogen peroxide soak it for stains on occasion. Hydrogen peroxide over night will do the job.

I live with people, guys actually, and no one ever notices.

I feel like I should say "But guys never notice ANYTHING" but I wouldn't want anyone to miss the idea that I was joking. (Well, at least half joking. I think no one would notice, guys or not.)

I clean mine with an unscented soap while in use, then at the end of my cycle use a rubbing alcohol pad (can purchase these from any pharmacy). I'm not sure if this is absolutely necessary - probably not, but I prefer this to boiling in a pan for 5-10 minutes.

This link here provides reassurance that you will not harm your silicone cup by using rubbing alcohol: http://menstrual-cups.livejournal.com/1649971.html

I have this cup,the old one. I have cleaned it with rubbing alcochol and hydrogen Peroxide several times, tough I usually can boil it. Anyway I can report that no harm done, my 3 year old cup is like new.