Regular vacuuming or sweeping is the best way to maintain the finish. Then damp mop with plain water or add just a drop of liquid dish soap. If the floor has some tough spots to clean, use a white, nylon backed scrub sponge. This will keep soil from wearing away the surface. However, if time and traffic eventually dull the glossy top layer, you may want to add a floor finish or wax to restore the shine. Choose any good commercial floor polish or try a self-polishing, metal interlock floor finish available from a janitorial supply. Traffic areas may need finish applied more often than the rest of the floor. It's a good idea to keep doormats at all the entrances to your home, as they will catch much of the dirt that could eventually damage your floors.