Thank you Asta and Potato for the advice! The only figure I'm a bit worried to wipe down is the Hasbro POTJ Darth Vader's bodysuit, which is made from a pleather-like material. It might be contaminated by the mildew spores, but there are no stains showing.
any reason you still holding onto Hasbro Darth Vader? If it's not sentimental i think you can buy the newer versions from Hot Toys. and if it flakes, it probably has black fabric underneath.