Stainless steel totally works - we use it in this house all the time.

For the breath - parsley and mint are both good. Munching down a single coffee bean is meant to work, but surely that just gives you coffee breath?

Also, a yoga technique is to hold your teeth together and inhale through your mouth, then exhale through your nose. Helps.

Ergh. I hate onion breath. I drink like 6 billion litres of water. And it doesn't fix it, but does stop me breathing on people.