Nothing really works on this kind of mildew. The only thing you can do is replace the calk. Question is whether there's other caulk out there that won't be susceptible to mildew growth. I suspect that the manufacturers would be using it if there were such a think.
If it's really bad, there is a product that you can paint over caulk to make it white again. I think it was designed for grout originally. Not sure it will stand up to weather. You could try painting it with bleach but you might affect it's composition and if you spill it, it might do more harm than good.
Phil
|