Really? Never heard about that way of doing things in all my years varnishing. Regardless, first you need to get the teak where you want it, before you put on any finish oil or varnish. Just wet with water and that will show you the color/condition of the wood, and if you have removed all staining, etc., or if it needs more "work", using the appropriate wood bleach, letting the sun's UV work on it, etc. Some staining may never come out. Remember to light sand again after water, as it will raise the grain. Then for varnishing, start with a thinned coat (50% varnish and 50% thinner) for first cost, then sand and build up with 100% coats (or slightly thinned depending on weather and brush ability) from there.