Clean a butcher block that just came from a restaurant or butcher shop with soap and water. Avoid using excess water and wipe soap off with a damp cloth. Wipe again with a clean damp cloth. To sterilize the block, spray with solution of 1 tablespoon of bleach in a quart of water. Seal the cutting surface with linseed oil. After using it, wipe it clean with a little bleach water for disinfecting and odor control.
Look for discoloration, rot and check for a rancid smell if you acquire a dirty old butcher block. Scrub with hot soapy water and a stiff bristle brush to loosen old grease and fat in the wood. Do not soak the wood. Wipe dry and clean with a brush and the solution of bleach and water. Any cracks or nicks in an old butcher block should be filled with wood filler and sanded smooth, starting with 50-grit sandpaper and finishing with 100-grit sandpaper. Finish by rubbing in a coat of linseed oil.
Scrub the butcher block if it is severely stained and damaged. Let it dry for 24 hours. Take the top 1 inch of wood from the top of the block with a plane if the butcher block is side grain wood. Use an orbital sander if it is made from end grain wood. Clean with a tack cloth, spray and wipe with the bleach solution. Reseal with linseed oil.
Wipe the restored and sterilized butcher block clean with a soapy cleaning rag or sponge, or a rag dipped in weak bleach solution after each use. Reseal the block with linseed oil when the wood loses its patina.