Oops
I pressure washer the van once a year!
Its a VAX came with extension poles and brushes, bit like a powered caravan cleaning brush, spray snow foam on the roof, brush it over with water pumping threw, pressure it off, clean as new.
Awning channels use the pressure washer at close range to get all the gunk out.
Snow foam all 4 sides, then stood well back blow over the van with the washer
I think that's maybe the issue here, being too close, bit of common sense required.
I remember years back we had a 3 phase washer at work, incredibly powerful, a sales rep wanted to use it to clean his Nissan I think it was, has to be 35 years ago, anyway he started off OK, then when it came to rinse the washer punched a hole through the wing!