The tough film provided by this varnish protects the painting surface from dust, dirt and surface abrasion. This protective varnish may be thinned with water (not exceeding 35%) and should be used as a final topcoat only – not to be mixed with other mediums or paints. Not for exterior use. It can be removed with household ammonia (5% solution) diluted with water. This varnish must be removed before over-painting.