Indeed the entire cage, atleast a weekly cleanout. Bacteria of various kinds colonize all areas and all enviroments, especially substrates, furnitings and water sources (dripper resevoirs etc). Food insects and your lizard defecate and dead insects (or half chewed ones your lizard drops) decay.
While nature isnt spotless, neither is it static and unchanging. Wild lizards and bugs 'move on' and dont remain near sources of harmful bacteria for long, and ofcourse Sunlight (UV) degrades waste, sterilises and the elements breakdown these things, not so in your enclosure.
Most folk aim for attractive and naturalistic cage design with live plants, which generally keeps chams happy, but at the same time, put it together with a little forthought to removal of said plants, furnitings etc, so that it dosen't take 3 hrs to properly clean up.
Tips: Try to avoid the permant installation of branches vines etc by screwing, nailing, gluing in place, rather use an easily removable method such as branch end supports, hidden plastic ties etc.
Excepting some species, most chams dont require substrate at all, eliminating on place for bacteria. For those that do, spotclean more often and change all the substrate regularly, unless using natural (biological cleaning) methods such as the inclusion of springtails and other bio organisms.
For general surfaces, a jolly good old fashioned scrubbing with hot soapy water, a dash of disinfectrion agent and good rinse and sun dry work well indeed to keep background bacteria levels quite low, and thus, lessen risk of disease.
For water dripper/mister resevoirs, A good cleaning weekly, Daily for small systems, to remove colonising anaerobic bacteria and algae etc from the resevoir itself and associate delevery apparatus (tubibg, nozzels) etc.
Never leave traces of chemicals of any kind on your lizards enviroment, Always rinse and rinse again.
