Seal watermarks with NEO Stain Sealer, NEO Universal Undercoat or NEO Road Marking Paint. NEO Stain Sealer is the correct product for this purpose as it seals the watermark and is quick drying due to its alcohol basis. The other two products can also be used, but it is not recommendable due to the long drying time (universal undercoat) and the aggressive solvent (Road marking), which might damage the substrate. Paint one or two coats NEO PVA of choice.