Cedar wood, along with other types of fine wood, is compatible with polyurethane protective coatings. These are a great way to keep oil, dust, dirt, and other debris from damaging or dulling the surface of your cedar furniture. If you’re going to apply polyurethane to a piece of cedar furniture that’s not brand new, we recommend scrubbing it with a combination of fine cloth and hot water first. Then, let it completely dry off before you start coating it with polyurethane. Should you fail to do this initial cleaning before the first coating — chances are that the wood will become ingrained with imperfections such as oils and dirt.