Re: Don't sand first!
I like gray if it is clean.
The regime I try to use but sometimes I don't:
Clean the teak. Then use Deks Olje #1 to oil and protect it. Protects and is pretty for a couple of months. Slowly grays but teak doesn't erode too much because of the oils and hardeners in the Deks. Each spring use lots of water and a green scrubbing pad to clean and repeat.