NAM Art Masking Fluid is a liquid used to mask out the areas of an artwork before the colour is applied. It leaves the surface underneath untouched, retaining the original colour of the page. NAM Art Masking Fluid is ideal for working with watercolour or airbrushes. Made from latex and ammonia, it is removed easily, by gently rubbing it off with either your fingers, or an eraser, once the paint has dried. For best results, make sure you remove within 6 hours and apply to dry paper. Clean brushes with brush cleaner or soapy water after use.