Thanks for the tip about the humidifier, I'll definitely investigate!
the Zoomed reptifogger I use is pretty good, but it's limited in terms of water bottle capacity. I use a hygrotherm with it, and the fogger does seem to struggle a little maintaining the relatively high humidity needed for my BRBs. I have also heard that the fans break easily, and though its too early to tell, the fans are starting to whir loudly.
I will keep the current ones clean, but I think moving forward I'll stick with maintaining humidity via substrate, water bowl evaporation and enclosure ventilation. (all recommended by those kind enough to share their experience!)
Many thanks!