Rustins Grain Filler is supplied as a paste which is thinned with white spirit for use. It is applied to wood before finishing to fill the pores, preventing sinking of the finish. Available in mahogany, natural, oak and teak. The natural shade can be thinned with Rustins Wood Dye so that filling and staining can be carried out in one operation. Rustins Grain Filler. Colour Natural. Size 230 Grams.