I got a little problem i'm not quite sure the best way to fix. I did an outdoor sign, vector letters painted. I finished it with a couple coats of water base spar urethane, brushed on. After it dried, I noticed that some of the finish pooled in the bottom of the letters resulting in small bubbles and a milky appearance. What is the best way to resolve this? I could paint over it I suppose or try to sand out the excess. Any suggestions?