Well mine has been sat in open air stood for a year now. It hasn't gone pink, I used Meguiers scratch x to remove any oxidation, then megs 3 step deep crystal polish (paint cleaner, polish then carnuba wax) then some autoglym sealant then harley carnuba proper wax. (or megs NXT)
This has left it gleaming like new without any further intervention, its well and truly protected. Not cheap for all this stuff but halfords has an offer (3 for 2) on this stuff at the moment, will cost you about £40 for the lot.