You should follow the instructions of your teak oil, but generally, here’s how it’s done: 1. Strip existing finishes. 2. Apply teak oil with a paintbrush or rag, wiping it into the grain parallelly. 3. Wait for 30 minutes and add another coat of oil. 4. After 15 minutes, wipe the surface dry. 5. Let the oil sit for 8-10 hours.