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That's very cool Pat!!  We actually used to do a similar contract on a by monthly basis.
I know the pics don't do justice to how well that equipment probably really turned out.
What is even better is the ability for people to network on this forum and team up for challenging jobs.  Well done Pat and Will!!
Here's a pic of the thing we used to clean.
Though it may not apply to non pressure roof cleaning that is still a very cool post to share.