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A few years ago, there were a number of devices that came on the market that essentially blew ozone through the airflow pathways in PAP devices, and this was supposed to be a substitute for disassembly and scrubbing (which is a lot less convenient). While nobody has said these devices and the ozone methods actually damaged the foam, replacement PAP units all are not warranted if ozone cleaning devices are used. I don't know if this is the only "cleaning material" to which the article refers.

Very likely some cleaners also have some solvent, though there is an explicit warning about UV and ozone[1] sanitizing:

https://www.fda.gov/medical-devices/safety-communications/ce...

https://www.fda.gov/medical-devices/safety-communications/up...

but I believe that more than anything else is the quality of this PE-PUR foam that is lacking.

[1] ozone sanitizing treatments have been found to damage a lot of materials (besides metal which oxidizes very quickly also rubbers) and actually ozone chambers are used to test rubber materials durability

Ozone or active oxygen from what I can gather