Double Ended Tin: Fine and Corse Grade. Easy Sanding and Smooth Spreading. Formulated for Valve and Seat Grinding Applications. Effective in Removing Burrs, Surface Defects, Corrosion, Gums and Carbon Deposits. Quick and Easy to Apply .Apply a small amount of paste to valve seat .Avoid contact of the grinding paste with the valve stem and guide. Grind the valve in the normal manner until a uniform seat of the desired appearance is obtained. If the seat is badly pitted, first use a coarser grade paste then trim with the fine grade. When a satisfactory seat has been obtained, clean off well and degrease with a suitable solvent such as paraffin before valve reassembly.