The best time to remove your semi-permanent varnish is when the nails are growing back: we then see a demarcation between the skin and the varnish. Our tips for removing your semi-permanent varnish To remove the semi-permanent varnish, you can go to an institute or do it yourself, by purchasing a kit in an institute. The technique used by beauticians is to wrap the nails in cotton wool soaked in acetone and wrapped in aluminum. At other institutes, you may also be asked to soak your fingers in acetone to soften the polish so that it can be removed with a boxwood stick.