Yes, as long as the previous finish is not lacquer or shellac. Be sure to test the selected colour on a hidden spot to see how it will look over the original finish. To prepare the surface, make sure that the finish is clean and has had all wax and polish removed. Then lightly sand with #180 or #220 sandpaper.
Then thaw meat, add seasoning and press into strips or sticks, and place on trays to dry. Depending on how thick meat is cut, how heavily dryer is loaded, and the humidity, jerky takes from 4 to 15 hours to dry.
If it snaps easily, it is overdone. Remove the jerky from the dehydrator immediately if either of these is the case. Return the jerky to the dehydrator if it bends easily or feels moist to the touch. Check it every 30 to 60 minutes until it is done, then remove it from the dehydrator. Depending on your dehydrator and the thickness of the jerky, it may take between four and 12 hours for your jerky to fully dry.