^^The green thing is called patina. It's supposed to make your cymbals sound warmer. I don't mind having it or not.
Ako, I never clean my cymbals. La lang, tamad (hehe). If ever, tuyong basahan or slightly basang basahan ang ginagamit ko. No solvents except water, if ever. I tried Groove juice, pero if you read closely, it's made for brass, not bronze. I tried them on my A's dati, at naging dusky yung color at parang camouflage yung itsura. I've stopped using it on cymbals... it's great for hardware though.
Pag nasa cymbal bag, I make sure na walang metal-to-metal contact between 2 cymbals. Like now, I usually have 2 or 3 cymbals in one pocket ng bag... I'll have one cymbal (or yung in-between kapag 3 sila) wrapped in a t-shirt. I don't do this with the hats though, kasi same size lang sila... they fit together snugly and won't slide or create that much friction compared to differenly-sized cymbals.
Plus, I don't put the bag down na nakatayo... always nakahiga. If I commute with my cymbals and I have to sit down (like sa jeep), I put the cymbals somewhere on my shoes where it wouldnt hurt (like yung sobrang space sa may toes). Other than that, I just put it on my lap.
And... like legnacilyz said... no metal to metal contact sa stand. Mortal sin of cymbal care yan.