Properly cleaning a range hood involves removing build-up from the exterior of the hood, as well as the filter inside. Start by removing the filter from the range hood. Many popular range hoods have permanent filters that are dishwasher-safe. You can either place the filter in your dishwasher for a quick and easy clean or use dishwashing liquid, hot water, and a soft nylon brush to thoroughly scrub the filter. Allow it to dry completely before reinstalling. How to clean the hood depends on the type of material. Most metal hoods can be cleaned with a degreaser. Use a clean cloth with warm water to rinse all surfaces after they have been cleaned. The exterior of the hood can also be cleaned with a degreaser and soft cloth, except in the case of decorative wooden hoods, which should be dusted on a weekly basis.