Clear Topcoat sealer is a soya oil “penetrating sealer” which means Clear Topcoat penetrates deep below the painted/stained layers to the surface. Clear Topcoat creates a high-performance durable bond between the layers of paint/stain and surface. As the sealer soaks into the layers and surface, occasionally the sealer will re-wet or activate things such as tannins or cleaner residue below the paint or stain (sometimes invisible to the naked eye). If painting then sealing with Clear Topcoat, we recommend the surface be sealed and cleaned first with mild cleaner followed by warm water to remove any cleaner residue prior to painting. After painting, we recommend a small test spot of sealer to look for potential bleeds and surface reaction.