Funny you should ask!
I was about to write a little posting about entitlted "black streaks, greystreaks, brown streaks and stains" or some such. I have given a done a lot of thinking and experimentation on this subject, especially as we have had quite a bit of input on this from our customers. It's no coincidence that "black streak remover" is one of the fastest selling products in most marine stores. However, it could be renamed "wax remover". Streaks are of several sorts. The most common black streaks caused by pollution runoff (car or plane exhaust in rain) of more locally by diesel smok on the transom. I used to have a big problem with my boat when it was under the flight path. Being essentially oily, these streaks will be absorbed into any wax, including the wax component of our superwax. If you don't believe this, try dipping a white candle into old dirty engine oil. The same happens with pure carnuaba or even our synthetic wax. This is because wax is essentially just a very hard fat! Generally you remove the wax and the streak goes with it, then you touch in the local area. Our superwax is only readily removed by our cleaners which also remove such marks. One customer in particular has thoroughly researched this and just uses some IG Pink in a sprtizer bottle, well diluted with water and uses microfiber cloth. I found that this also works great. The amount of pik used costs about the same as a bottle or more of "streak remover: (WM product is probably is polysolve em, plus some detergent, and lots of water) However, this is better than the streaks getting down into chalky pores of the gelcoat. If this happens, our cleansers (especially cleanser/conditioners) are the only thing that will work except for heavy compounding. Grey streaks are either due to bottom paint dust (a real problem in boat yards) or mineral-type dust (a mild acid type "water spot remover" (usualy citric acid or diluted oxalic acid) works on the mineral-type dust. Over here we get brown dirt that is actually attracted by a magnet (lots of iron). Bottom paint dust is dissolved by our cleaners and IG Pink is ideal for removing this type of dust from non-skid that is not sealed in any way. My boat was stored for a couple of years at Ala Wai Boatyard and was sometimes just covered in bottom paint dust. The other sort of streaks (yellow- rust stains) are easily removed from pores with our cleaners unless there is deep penetration. I am still trying to find the best acid-type remover for this becuase I have a very bade rust stain on the roof of my pilothouse, around a bold head and a small crack in the gelcoat. How to prevent? I am now using our new Mirror Hard Superglaze over the old superwaxed surface on the areas susceptible to runoff. Becuase it has NO wax component, the thoroughly cured resin is stain-resistant. I find that microfiber cloth and a little water or (better) silkenseal works fine to remove grey streaks and black streaks do no penetrate and are so easily wiped off. If the finish is still a little oily (it tends to sweat for a day or so). The microfiber cloth and water (or water with a v. slight amount of IG Pink) works fine at removing any light pollution. Then it will be stain-resistant. Similarly our non-skid sealant is stain-resistant acts as a barrier to really bad stains like old engine oil or cetol. If it stains the sealant at all- just remove with a little pink and reseal! I bet this is the most boring reply I have ever written Jim Willis PS then there's stains from lake and river water etc. Use oxalic acid-based stain remover. But I bet the gelcoat can be sealed by Superglaze around the waterline too. Any volunteers out there?
