algae

Hi guys. I've a 2008 A4 Convertible that needs a bit of TLC. I'm looking for advice regarding the best products to use to remove the mould / mildew. I was initially looking at a circular drill bit extension brush or am happy to go for a handheld brush if better, I'm guessing the brush bristles...

What are your guys cleaning methods & products for the soft top? My top is in pretty good condition and I'm looking to keep it that way. Although I have noticed a little build up of algae which is hidden where the soft top meets the body of the car rear passenger side.