Every tech in my shop swaps sensors wet, I do it dry and my come back rate is near zero
I work at a repair bench in Tucson and for the past 6 months I have been doing all my full frame sensor cleanings with a dry method only, no Eclipse fluid, no swabs soaked in methanol. The other three guys in the shop think I am nuts and keep telling me I will scratch a cover glass eventually, but my come back rate on sensor cleans sits at about 2 out of every 100 bodies, and theirs runs closer to 12. The trick is a rocket blower first, then a clean static brush, then a dry sensor swab with light passes under a loupe, and you never touch the glass with anything wet unless it is oil or a welded dust spot. Last Tuesday a guy brought in a D850 with a big blob on the top left corner that two other shops had already wet cleaned twice, and I got it off in 4 passes dry with zero residue left behind. The wet crowd says dry just moves dust around, but in my experience the fluid is what streaks and attracts more junk after the fact. If you have been fighting streaks on your own sensor cleans, try a dry pass before you reach for the fluid and let me know what your come back numbers look like.
A buddy of mine ran a small shop in Phoenix and had the same thing happen. He kept getting streaks after wet cleans on a client's 5D Mark IV, three tries in a row, and finally just hit it with a blower and a dry swab and the smudge came right off. Turns out the fluid was leaving a film that grabbed dust every time the guy changed lenses, so the cleaning was actually making it worse. He switched to dry first for most jobs and his repeat visits dropped a lot over the next few months. Curious how you handle the ones that are truly stuck, like pollen that's baked on?