Preferred method for removing mold & mildew from album covers

use go-gone liquid. 

I've replaced quite a few covers surfing in good will or similar stores. For smell you can use Ozzium. The way it works that you should place your smelly items let's say inside your car or bathroom sprayed all over with Ozzium and than close the doors for 20...30min. The car would work best
With goo-b-gone I cleaned large number of album covers as part of my business. Nothing work best there.