I would certainly agree with ANM. This possibly fatal idea might have gotten started because of valid speculation that the ether might kill virus when used as an anaesthetic in a hospital. (Patients on ventilators might get anaesthetized to keep them from overbreathing when on a ventilator, which would harm their lungs.) It's not for amateur administration.
Remember Michael Jackson? Plus, there's possible explosion :)
https://www.bmj.com/content/368/bmj.m627/rr
Re: Covid-19: a puzzle with many missing pieces. "Diethyl ether and COVID-19"
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And this:
"During the second half of the 19th century, ether was in vogue as a recreational drug..."
There is no proven method of prevention other than washing your hands and social distancing from everyone.
DE won't act as a sterilant for your lungs and no one will ever study it for that purpose. Toxicity. Acute: harmful by inhalation in high concentrations which can cause inebriation, sedation, unconsciousness and respiratory paralysis. Diethyl ether is irritating to the respiratory system but these effects are usually reversible on removal of exposure.