Looking for a "silver bullet" primer that covers everything unwanted? Use the one contractors keep in their vans: Rust-Oleum Zinsser BIN Shellac Primer Spray. As the original, shellac-base primer-sealer, nothing is better at permanently blocking stains, odors and wood knots. Zinsser BIN shellac-based primer is a primer-sealer, stain blocker recommended for almost all surfaces. It blocks grease spots, fire, smoke, water stains, ink, crayon, knots and sap streak stains and seals odors resulting from water and fire damage. It seals knots, porous wood and spackled areas. It sticks to ceramic tile, glass, metal, plastic and hardboard.