Absolutely fantastic bike, great find. That is the genuine McCoy and well worth keeping and spending time on. To put that more clearly, you have a very collectable bike. If you aren't going the "full restoration" route (not my choice, but it's a defendable optionā, I definitely don't reccomend acid of any sort. Either you wan't it brand spanking new looking and have a stash to spend on it, or you "stabilize it" whilst immproving appearance a bit, and giving it some "patina" compatible with a very collectable vintage machine. The chrome, not a lot to do except rub with 000 wire wool (lightly) and chrome polish. Then rub in loads of oil and run and rub and rub. The painted stuff, you can scrape away the worst rust with a scalpel, and again rub in a real load of oil (coton rag). Hand polish any aluminium. Just my opinion, take other better qualified people's advice before mine