Many modern wooden furniture pieces come with a protective polyurethane coating, but for older items, nothing beats wax to protect against dust and moisture. Choose paste wax, the solid kind sold in tins. Natural (clear) wax works on any wood, but dark wood may benefit from tinted wax (it will mask tiny scratches). Begin by cleaning with a mild solvent, such as mineral spirits (test first in a hidden spot).Then cover the piece with a thin, even layer of wax using a cotton rag or cheesecloth. Let dry ten to twenty-five minutes; buff vigorously.