I am trying to stencil on a wooden plaque for a wreath that I am making. I am using Delta stencil creme (white) on the wooden plaque which I painted navy blue using acrylic paint. How do I remove any white smudges so that when it dries, you can't even tell I made the mistake? If I use the navy blue acrylic to paint over the smudge, the blue paint is only going to dry darker than what I painted the plaque in the first place. I have tried doing that before. Thanks.