To clean a wooden hot tub, follow these steps:
Drain the hot tub and remove any debris or dirt.
Clean the tub's surface with mild detergent and a soft-bristled brush, being careful not to damage the wood.
Rinse thoroughly with clean water.
Apply a wood cleaner and brightener, if needed, and scrub with a soft brush.
Rinse again and allow the hot tub to dry completely.
Apply a wood sealant to protect the wood from moisture and UV rays, if needed.