TJack

I use a product called wet & forget around the place to kill algae on the patio, walls, convertible car roof, boat, boat covers, shed, bins etc. Basically I spray everything with algae down once a year I usually give them and any other green bits from parking under trees a quick spray on my way past. One spray leave it to dry, looks a bit like a local cats pee'd on it until you next wash it but resist washing it for a little while, they clear up over a few weeks or so and stay clear for a year or so. Certainly until I next wet & forget a year later. Saves taking them out. Not worth buying just for the fog lights but I use it anyway as it saves a load of jet washing on everything else. Not found anything that it damages yet.