OPI Nail Lacquer Thinner 60ml Nail Lacquer Thinner by OPI improves lacquer consistency for optimal results. Formaldehyde-Free. Add 2-3 drops of this thinner to your favorite nail polish shades and shake well to revitalise them to their former glory. Rejuvenates lacquer? Use just three to six drops to maintain proper nail lacquer consistency.? Ensures lacquer integrity? Formulated specifically for use with OPI Nail Lacquer. Contains proper solvent blend without additives that could compromise lacquer formula. ?Formulated with a carefully selected blend of solvents to rejuvenate overworked polish.