
Have to agree with Harry myself; I kind of prefer the greyish look! Don’t scrub too much as it can make the teak go greyer that before; almost black in some cases.
You can buy specific teak oils that will give it back a warmer colour. Oil intensifies the colours and grain patterns of wood and gives the wood a rich, warm appearance. It is arguably the most attractive of all wood finishes. The sorry truth is that teak will last just as long if you don't oil it, since repeated between-coat scrubbing wears the wood away. But oiling teak isn't about protecting the wood.
Teak oils are primarily either linseed oil or tung oil, bolstered by resins to make them more durable. Linseed oil tends to darken the teak, but it is significantly cheaper. Tung oil doesn't darken the wood, and it is more water resistant than linseed oil-a notable advantage for boat use. However, a month or two after application, it may be hard to discern that much difference since both oils carbonize in the sun and turn dark. Proprietary teak oils address this problem with various additives, including pigments, UV filters, and mildew retardants. Some that perform admirably in one climate are reviled in another. If you are going to oil your teak, make your teak oil selection based on the recommendations of other boatowners in your area.
Wipe up any drips or runs on fiberglass or painted surfaces, or the resins the oil contains will leave dark, nearly-impossible-to-remove stains.