Just soak them in the tub, and lay on towels to dry. The most important ingredient, is to put a splash of Ammonia into the wash water and a small amount of laundry detergent. Ammonia also neutralizes other odors, such as cat pee and such. You could even mix 1 cup of water with 1 tbsp of ammonia into a spray bottle, and spray your blocks, and let dry on a clean dry towel. Test on one block first, if the ammonia is too strong it will also take the colour out of your fabric, but make sure to rinse. And by the way, you came across a very nice addition to your stash. Hope you are able to enjoy the finished product. Auntie B