You can inexpensively refinish a lightly scratched wooden floor by layering a new coat of finish directly over the old coat without sanding first. Chemical refinishing replaces the mechanical abrasion that sanding offers, allowing the new coat of finish to bond with the old coat directly.
Chemical etching products such as the one included in the Varathane Renewal Floor Refinishing Kit use a chemical process to roughen a floor's laminate finish, allowing the homeowner to apply a new layer of laminate finish. In many cases, this process leaves a finished wooden floor looking brand-new in less than a single day.
While chemical refinishing products produce great results when used on floors with normal wear and superficial scratches, it does not cause deeper scratches to disappear completely. FamilyHandyman.com suggests sanding when heavy traffic patterns have completely worn away the floor's finish, as chemical etching products may discolor bare wood on contact. You can use chemical refinishing products on a wide variety of wooden floors, but not floors that have been coated with a wax finish.
To test your floor for wax, let a few drops of mineral spirits sit somewhere on the floor for a few minutes and then wipe it away with a clean white rag. If the rag shows brown or shiny residue, the floor's finish is waxy and must be sanded for the best results.