I live in a Lindal Cedar Home which is about 15 years old. the interior cedar walls which are EVERYWHERE are not clear, but are knotty to the point of distraction! They are sealed. I want to paint or ”wash” them in a warm white or gray color so that the knots are not so prominent. What would you suggest to ”treat” them to achieve the desired effect of not-so-knotty looking walls?Many thanks