Carpet cleaner heads - how tf do you clean one?

[NosyJosie]

I have a Tower carpet washer and the sucky nozzle bit that picks up the grossness from my carpets gets disgusting. I had this on my old Vax and it was the same problem.
Short of unscrewing the bastard thing, how do you clean out the sludge? I’ve checked manuals and online and can’t find a good answer

I had a Vax one I think it was and it was an utter bastard. I had lost the manual but watched a you tube video, which featured a cleaner a bit similar to mine. Might help to take photos as you unscrew screws and what order you take things out. The angle at which some things come out can be a bastard, lots of fiddling but it's possible. The gunk can be so gross.

I’m able to unscrew the bristle brush but not the whole head with the problem area. The vax I had was easier to lift and I could sort of rinse it out with a bottle of water but still not perfect. Literally the worst nightmare for a clean freak.