Attach a piece of 80-grit sandpaper to the bottom of an electric sander. Run the sander around the surface area of the butcher block, concentrating it in the area where the burn mark is. Repeat with 220-grit sandpaper.
Rub the surface with a tack cloth to wipe up all the dust from sanding. Pour equal parts bleach and water into a bucket. Dip a sponge in the mixture and wipe down the butcher block.
Soak a rag in white vinegar and wipe down the butcher block. Then add a dot of dish detergent to a clean, damp sponge and wipe down the surface of the butcher block.
Attach a piece of 360-grit sandpaper to your electric sander and rub it around the surface area of the butcher block. Dip a clean foam brush in mineral oil and apply a light coat to the top of the butcher block.