You may be able to renew a dull finish without completely refinishing the floor. Still, some hardwood floor manufacturers recommend that only professional refinishers tackle the job.
If you decide to do it yourself, begin by sweeping with a good broom and then vacuuming the surface. Next, use a buffer with an abrasive pad and/or fine-grit sand paper until the finish feels smooth. Another option would be to use a rectangular oscillating sanding machine. Hand-sand any areas that remain rough or irregular. Keep in mind that you want to lightly sand the top coat of the finish, not sand through it. Remove dust by sweeping, vacuuming and wiping the floor with a lint-free towel slightly dampened with water. (Make sure the towel has not been treated with fabric softener or anything else.) Allow the floor to dry completely before applying a single coat of polyurethane finish. Check with the manufacturer of the new finish if youâ€™re not sure itâ€™s compatible with the finish already on the floor.
For a waxed floor, apply a mineral-spirit based renovating product and buff with a No. 1 steel wool pad. Allow the floor to dry completely. Next wax and buff. Keep in mind that these steps will brighten the appearance of the finish, not lighten the wood itself.