Use only warm soapy water when cleaning the shelves. Use a hard wrung out cloth and wipe immediately with a soft dry cloth. The solid oak is treated with oil. If the surface of the wood dries out, you may be able to restore its original glow using canola oil. Apply a thin layer of oil to the product, then dry immediately. The wood will probably take on a slightly darker tone after applying oil. Please test on a small section of the shelf before applying oil to the entire unit. If you are in doubt, contact a professional for advice on how to treat the wood.