I have recently purchased a log home. I have found mildew (not a lot but enought to concern me)growing on one of the ceilings. This is in a corner room that I have not used much right now. The ceiling has a natural stain wood finish and also looks like it has some type of finish over that which makes it shine. What is the best means to wash the mildew off without hurting the finish and keep it off. Thank you for any help!