Aluminium alloys as a general group hate salt...4000 and 5000 series alloys are more resistance to corrosion but not immune from it. Take a set of alloy 700c rims (say 6061 T6 alloy pretty common) ...expose then to a few hours of salted winter roads, put them away for a few days with out giving them a damn good clean and you will have innumerable pits in the alloy. Leave them coated in enough salt for long enough and they will turn into a 'crumbly bit of aluminum crap'. Salt kills alloy components. The Dutch philosopher Desiderius Erasmus puts it like this, 'Prevention is better than a cure...'
Clean it more often...
