Ensure the surface is clean and dry; sand it smooth with 100 grain paper, or 300 if stained. Apply the first two thin coats using a natural brush (or synthetic for water based varnishes), following the grain of the wood. “Tip off” to improve and even the finish whilst the surface is still wet. Leave for a day, then sand lightly and evenly with 350 grain paper before applying an additional coat. Allow several weeks for full curing before use.<p>For best results, work in a dust, fibre, and debris-free low humidity space with fume extraction as ventilation rather than open windows.