It was actually cedar not teak. I washed down with oxi clean and lightly scrubbed it with a plastic bristle brush. You can see the spotted foot rest on the right and the oxy cleaned rest on the left. The home owner was very happy and asked me to clean some more of their cedar furniture. I still may try oxalic acid to brighten it up more if I get the chance.
Admittedly, I was to blame for a similar instance this year. We always keep extra supplies on the truck just in case, so the customer got a 'free' treatment on their teak bench. They were thrilled and never knew I'd made a mistake. Basically, I did not rinse it down right away even though I had pre-soaked the wood. No pics though! Great work on fixing it, Chris. You should have a loyal referral now.