I've recently cleaned our awning. Even when the weather is warm and dry, the awning is usually wet with condensation in the morning, and despite wiping it before rolling it in, it inevitably remains damp, and over time, it becomes discoloured with mould. I used a cleaning product called Dettol Mould and Mildew remover (spray in green plastic bottle). I used it to clean both the underneath and the top. I rubbed it in with a scotchbrite sponge, then after 10 minutes, wiped it with a wet cloth. The top in the centre nearest the vehicle was difficult to access, so I used a squeegee floor mop for that section. It has all come up like new. I'll be doing this every year from now on!