Does WD-40 preserve wood?

WD-40 does not truly preserve wood in the long term and is not recommended as a wood preservative, although it can provide a temporary cosmetic improvement. WD-40 is primarily a water displacer and solvent made from petroleum distillates, not an oil that nourishes wood fibers. When sprayed on dry, faded wood, it will make the wood look darker, richer, and more vibrant immediately because it fills surface scratches and adds a thin oily sheen, which is why some people think it preserves wood. It can also help remove sticky residue, crayon, or tape from wood and can displace moisture after a spill. However, it evaporates relatively quickly, does not penetrate deep enough to condition wood, does not harden to protect, and can actually dissolve existing finishes like wax or varnish over time. It can also interfere with future refinishing because its residue repels stain and polyurethane, causing fisheye defects. For true wood preservation, you should use products designed to penetrate and protect, such as tung oil, linseed oil, Danish oil, teak oil, or hardwax oils that harden in the wood and protect against moisture. For surface protection, use beeswax, Feed-N-Wax, or polyurethane. So while WD-40 can make wood look better for a day, it does not preserve it.