Hartl did suggest a better idea: burn the old masks as fuel. Burning old masks would be better than digging up more oil (assuming the old masks are burned hot and clean etc!)

It’s not biohazardous waste if you’re allowed to throw it in any trashcan. Also, viruses can only survive a limited time on the mask, so if properly stored after use for the appropriate time, then this is perfectly safe to do to your own / household’s masks

These are already widely recycled. In the UK places like WILKO are collecting used masks in stores to recycle into plastic boards. There’s also a company in France using old facemasks from collection bins to manufacture new PPE. I agree that 3D printing is a gimmick, but being more conscious about plastic waste is not. Burning plastic is a cause of air pollution and not to mention toxic to most living things.

I think this post is an example of what is possible if the attitudes towards recycling change, in particular single use plastics. What needs to be addressed is how plastic waste is collected (not just from PPE) so that it doesn’t go to waste. Have a look at the precious plastics company https://preciousplastic.com/ – they sell a range of machines for small scale plastic recycling and share their work to help create an alternative global recycling system.

Masks being medical waste was stated by the comment that started off this subthread. I was responding to a comment that seemed to imply that there were no problems as long as they were your own masks being recycled, which I think is a defensible position only as long as any organisms that accumulated in the masks are (relatively) harmless, unable to survive the recycling process, or nobody else gets exposed to it until it’s gone through some sterilizing process.

If masks aren’t medical waste, then there’s likely no real problem with non-sterile recycling of them into filament.

As for other clothing, you have a point, but I don’t consider it pertinent. We’re discussing recycling masks meant to prevent transmission of a respiratory disease. If we were discussing recycling clothing while dealing with a disease transmitted via perspiration, skin flakes, or something similar, your comment would be more applicable.

By that logic all worn clothing and any item potentially exposed to human breath is medical waste too.

And nobody else will ever come close to this filament? I’m willing to accept that once it’s been through a printer’s nozzle, it’s likely to have been heat-sterilized, but unless the masks, granules, filament extruder, and everything else involved prior to that are sterilized, it all should be considered either biohazardous waste or contaminated items.

Technically it is denaturing/deactivating the RNA in the virus is made of deactivating the virus. but for the purpose of the average Joe Citizen who at best paid next to no attention in biology kill is a term they can grasp.