I would not presoak it with anything. I would just use the power washer with straight water, get the crud off, then go to work with the soaps and brushes. Don't get the power washer to close to the teak or you will find you are blasting off strands of teak. I would consider investing in an electric power washer. I have a little one at 1500 psi that cost less than $100 and it does a great job.
|