har.......會既mer ?? My Pradas' don't have this even over 10 yrs gor wor......nor my LVs.
BTW, 氧化 =/= 生銹 gor wor.......if purely oxidation, using a piece of cloth to clean may be OK.......but for rusts......the surface must have been scratched and then corroded.......no cure unless replacement.
Maybe you have to pay more attention to the store you put those bags in la......haven't you used the bag that come with the Prada to store it ?? If yes, it should be OK gor wor.........you should be more careful if live near the sea.