Teak refinishing and repair
First, sand off all of the previous finish. I would then, if necessary, bleach out the wood using one of the products available commerically. I would not use one of these two part teak cleaners; they are an acid which eats away the top layer of teak. After you prep the surface, I would put 5-7 coats of Eppifanes on. The first coat should be 50% Eppifanes / 50% thinner, the second 75% Eppifanes / 25% thinner. Sand lightly in between coats and make sure you tape off with a low tack masking tape like the blue- and green-line products from 3M.