Remove the hardware from the drawers, doors and windows. Determine what type of soil and wear they have.
Put painted hardware in a pot. Add a teaspoon of powdered detergent and a teaspoon of liquid fabric softener. Cover the hardware with water and bring the pot to a low boil. Let the water simmer until the paint loosens. Remove the paint with a soft brush. Use toothpicks or a dental tool to remove the paint.
Use a commercial hardware cleaner or soak the hardware in lacquer thinner or mineral spirits to remove varnish or lacquer. Remove the hardware and use a soft cloth to rub the surfaces. Repeat as necessary.
Sand the hardware lightly with a sanding sponge. This will help the paint or finish to adhere. Use a soft cloth to wipe off the dust. You do not need to sand if you are not painting.
Prime the hardware with a spray primer if you are going to paint it. After the primer has dried, apply two thin coats of spray paint for metal. Let dry between coats then wait a few days before reinstalling the hardware.
Buff the hardware to refresh the original finish if you are not painting it. Add a thin coat of spray lacquer to protect the finish. Allow to dry thoroughly before reinstalling the hardware.