Use a brush to apply this masking fluid to areas you want to block out when watercolour painting or airbrushing. Great when glazing or working in layers, or for areas you want to remain white or a lighter colour. Great for use in mixed media too. Its colourless nature ensures that the paper or canvas will not yellow. Directions for use: Brush onto paper or canvas in areas you want to block out, using a soft clean brush (not your favourite one as the latex in this product will ruin it). Leave to dry. Paint over the surface as desired. Once finished and the paint is dry, rub back with your finger or a Gum Eraser to remove the masking fluid.