Masking fluid is used to block out areas of an artwork, when working with water colour, airbrushes, acrylic etc. Once dried the masking fluid can be painted over and can easily be removed by gently rubbing it of with your fingers or kneadable eraser. This masking fluid can be diluted with water but never over 10%. Clean brushes with warm soapy water before fluid dries.
It is important to note that once the masking fluid dries it must be removed within 6 hours.