Blanks that are made with 100% resin (no other materials embedded) do not require any top coat finish. Just polish to a high grit with your preferred method. We recommend applying a top coat finish like CA glue to blanks that contain other materials embedded in the resin such as pinecones or wood to ensure the best protection as well as to get an even gloss sheen across the entire blank. Check out our guides for tips on sanding, polishing, and applying CA finishes on blanks