SEAL-ONCE must be applied to bare wood. If the surface has been previously coated with another stain or sealer, that product must be removed. Common practices for preparing your wood project include power washing, using a cleaner such as our All Wood Cleaner, sanding the surface or using a stripper to remove all previous stains and coatings Ensure all surfaces have been properly cleaned by using the appropriate SEAL-ONCE cleaner (All Wood Cleaner or Concrete/Masonry Cleaner). After cleaning, rinse the surface with water and allow to dry completely. Once the surface has been cleaned and the old coating has been removed, SEAL-ONCE products can be applied, according to the package instructions.