Up to date the best technique I've found is to spray some on whatever and then take a putty knife and spread it so it's a very thin coat so it looks like there's hardly any there....What little bit is there puffs up a little bit and looks pretty cool actually...I've done this technique on columns, roof and crypt sign I made last year..For cleaning the metal putty knife, I simply let it cure and then took a second putty knife and scraped it off..ZR