1st. hose off the cabinet. 2nd- make up a bucket of this solution-2 gallons water, add 3tbpsn spa chlorine, stir. 3rd, use boat brush or the like and apply chlorine solution to spa cabinet. pay extra attention to mold, mildew areas. Let solution work on spa for 20 mins, then hose off well. Let dry thoroughly for a few days, lightly sand-optional. Apply a waterborn stain with a medium body. See a Sherwin-Williams or Tru-Value store. couple coats will due. Take off cover clip hardware prior to staining. If there's an equipment door, make sure to hit the end-grain of the boards as well as the top and bottom of the door and inside wood framing it closes against. Think that will do.