Zinsser B-I-N Shellac-Base Primer, 1-Gallon, White Seals knots and sap streaks inside and out Absolutely the best interior wood sealer Seals water, smoke, graffiti, and grease stains Seals pet, smoke, and musty odors Sticks to all surfaces without sanding Shellac-base primer-sealer For interior and spot exterior use Greatest stain sealer Seals pet, smoke and musty odors Sticks to all surfaces without sanding