Polyurethanes are liquid plastic resins that dry to a durable satin or gloss finish. Polyurethane finishes are much more resistant to moisture and spills and moderate heat than traditional varnishes, and do not need much protection. Note most manufactured furniture is NOT Polyurethane coated, as it requires considerably more drying time and intercoat work to apply commercially.
Dust regularly with a soft dry cloth and wipe dry. When needed wipe with a moist cloth, not wet. This will remove fingerprints and light soil. When dirt or grime have built up, clean with mineral spirits
Wax or polish can build into an enemy. Remove it with a cloth dampened with mineral spirits. Clean small areas at a time. Wipe each area with a clean cloth before going on to the next. Wear rubber gloves to protect your hands, and dispose of them afterward, or wash in hot suds and air dry. Air-dry cloths used in cleaning to evaporate the solvent before disposing.