How often do you get asked from a potential client "how do you clean the awning?" Or if you use a pressure washer? The reason I ask is, for whatever reason, at least in my market, it's just not something we have to "sell."
I looked back and in 2013 we gained 23 (out of 31 bids) new, separate awning cleaning customers. Not one asked if we used a pressure washer or not and only one or two that I can remember asked about the cleaning process. The 8 bids we did not get, from what I could gather, was about our price being too high, and not because of how we cleaned the awning.
I agree with you though, if someone didn't know what they were doing, using a pressure washer could certainly cause some damage to canvas. But then again, you can screw up concrete, wood, stucco, or just about any surface that we clean everyday with a pressure washer too. But that doesn't stop us, does it? It's because we know what we are doing.......right?