The green is copper oxide and copper hydroxide. This is not the kind of patina you want. Luckily, I've found a little WD40 will often remove the green and leave the more desirable brown patina. This also may mean that your sax is staying wet in the case. You might try wiping it down before putting it in the case and leaving it out on a stand while at home.
A forum community dedicated to saxophone players and enthusiasts bought to you by Harri Rautiainen. Come join the discussion about collections, care, displays, models, styles, reviews, accessories, classifieds, and more!