Vacuum the exterior of the stones. Run a feather duster across the stones, getting out all the dust and debris from the cracks. Squirt an all-purpose cleanser all over the surface area of the stones. Allow it to soak for 20 minutes.
Spray a light coat of foaming tub cleanser all over the stones. Scrub the stones with the scrub brush. Combine 1 cup of Borax and 1 tbsp of dish detergent in a bucket with 1 gallon of water. Repeatedly dunk your scrub brush and your scrub the stones.
Rinse the stones well and pat them dry with an old towel. Allow the stones to dry thoroughly for 24 hours.
Apply an all-natural, untinted sealer to the exterior of all the stones with a 2-inch nylon brush. Coat each stone easily and uniformly. Apply one to two coats depending on your desire and how glossy you want the stones to look.