Water-based non-yellowing clear glue and varnish for napkin technique projects on glass, ceramics or porcelain surface. Place a napkin on a clean grease-free surface and apply glue on the top evenly. Leave to dry for 12 hours. Put an object into an oven. Heat oven to 140° C temperature. Bake for 30 minutes 140° C then turn off the heat and allow the item to cool down in the closed oven.