Formica is composite material, a plastic laminate that's both heat- and stain-resistant. It can be found on kitchen and bathroom countertops throughout the world. While resistant to the effects of most normal use, Formica can still be scratched, and even the faintest scratches can add up to a dulled, dirty-looking surface. Just because it gets a bit scratched doesn't mean you have to replace the Formica surface, though. You can repair the scratches yourself, returning the surface to a bright appearance and adding years to the life of your countertop.
Clean the Formica surface thoroughly using a mild detergent mixed in warm water. Use a sponge dipped in water to clean most of the loose dirt and debris from the surface. For ingrained dirt you should scrub vigorously with a heavy-duty scrub sponge, making sure to clean out any crevices or joints between the Formica and other materials.
Apply a little furniture paste wax to the end of a cloth and rub it into any small scratches in the Formica. Completely fill the scratches with the wax until the wax is level with the Formica's surface.
Take a buffing cloth and buff the surface of the Formica, concentrating especially where you've applied the wax. Buff in tight circles, starting at one corner and working your way across the entire surface of the countertop.
Use the putty knife to fill in large scratches or chips with Formica filler. Formica filler comes in a variety of colours and can be mixed to match the colour of your countertop. As with the smaller scratches, fill in the larger ones completely until the filler is level with the surface of the countertop, compressing the filler into place with the flat of the knife. The filler seals the interior materials and keeps the scratches from widening. Leave the filler in place for 24 hours to dry before continuing.
Buff the filled areas with steel wool, rubbing the wool lightly over the filled surface in a circular motion. Buff until the filler is completely smooth to the touch.
Spray furniture polish over the entire surface of the countertop and wipe the counter clean with a cloth. The polish should both clean the surface of the countertop and help the filler match the rest of the surface. The scratches will remain slightly visible, but the surface will be protected from further damage resulting from them.
While you can repair the Formica and keep the repaired scratches from further damage, the only way to completely restore your countertop is to replace the surface entirely. Repairs completed with the wax process are temporary and must be repeated when the wax filling wears away.