use what professionals use to speed up drying when they need to apply several coats on the same a day Klean-Strip® Japan drier. Its special blend of lead-free drying agents accelerates the drying ability of oil-based paint, oil-based enamels, varnish and polyurethane. It is especially effective in highly humid or cool weather conditions. Though Klean-Strip® Japan drier appears purple, it will not affect the color of your coating.