go to woodstrip.com, the web site for anderson's. find the phone number, use it, and ask for russell. he can help you with a de-greaser, a stripper, a deck wash and a brightener/neutralizer.
for mildew, chlorine bleach is the ticket--in some regions you can get liquid chlorine from a pool supply place cheaper than chlorine bleach. bleach is anywhere from 5 to 6% sodium hypochlorite; liquid chlorine is 12% or so. chlorine has a poor shelf-life--don't over-stock. to prevent damage to vegitation, thoroughly wet grass, plants, etc both before and after using the chlorine. when chlorine, or any other caustic is used on bare wood, it needs to be followed with a neutralizer to restore the proper ph to the wood.
russell is very patient and very helpful and will be glad to elaborate on the various matters i've touched on.
good luck
richard