As regards the stainless steel thing, I do have actual experience of a similar thing:
I used to work in a kitchen and one of my jobs was peeling onions - sack of them! Naturally, after half a day doing this, my hands reeked of onion. I could never get rid of the smell without have a long soak in the bath - until one of the older people in the kitchen told me to try a little gadget from Lakeland. It is a flat-pear-shaped lump of stainless steel. You just wash you hands with it, with or without soap.
Amazingly, it did indeed rid the onion smell instantly. Or at the very least, diminish it drastically, far more so than repeated hand-washing.
So, stainless steel may do something as regards odours, but I've no idea how or why.