333 Brushing Liquid is a slow drying solvent to ease brushing and facilitate the flow of specified paint coatings. Wipe down your canoe with this thinner to remove dust and pinesap, etc. Then follow up with varnish. Add about 10% of this to Goldspar 95 or Captains Varnish for easier brushing and better soak-in. Remember to pour out some varnish into a separate container and mix in some thinner. I don't recommend adding thinner to the original varnish can. You may want the varnish thicker on a different application.