Scrub the butcher block countertop with a mild wood soap and a sponge and let it dry completely. New butcher block installations do not need to be cleaned prior to finishing.
Make a double boiler. Fill a sauce pan 1/2 full with water. Place a metal mixing bowl into the sauce pan. Use a bowl that will sit on the rim of the pan with the bottom part submerged in the water but not touching the bottom of the pot. Double boilers are also available at kitchen supply stores.
Bring the water in the sauce pan to a boil then place the mixing bowl into the sauce pan.
Place paraffin wax into the mixing bowl to melt. Use paraffin wax that is sold for home canning purposes. Leave the wax in the double boiler until it is liquid. Check to make sure the water in the pot does not boil away while the wax is melting.
Dip a soft-bristled paint brush into the melted paraffin wax. Brush the wax onto the butcher block countertop until the entire surface is coated. Make sure to coat the edges of the countertop as you go.
Let the wax dry and harden for 12 to 24 hours. Scrape off any extra wax that has dried on the surface using a putty knife.