More recently: a 2017 mask decontamination study from Taiwan that compared a number of commonly-available solutions, using several mask types including N95:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5638397/

Surprisingly, the method that worked best was...

> "Place the test masks in a traditional electric rice cooker using dry heat for 3 minutes (149~164°C, without adding water)."

Apparently dry heat was much better at preserving the structural integrity of the different masks, compared to chemicals or steam.

> traditional electric rice cooker

Probably meaning one without a microcomputer.

https://www.youtube.com/watch?v=RSTNhvDGbYI

I would suspect if the general population was told to do this we'd have more disruptions due to house fires than from the increased risk of unboxing packages outside of the door, discarding them and then washing your hands and clothes.

What catches fire at 75 Celsius?

I don't think my oven can go lower than 200F.

If you have a thermometer you can turn the oven off manually as it approaches your target temperature. I do this for warming bread dough. Once you know how long it takes you don't need the thermometer.

If your oven is not accurate near 75 C. maybe you can use one of the other methods, from the pdf it looks like water steam could do the same job.

People can use a water bath like one of those sous vide machines. You seal the mask in a ziploc bag and weight it down below the surface. That should be a pretty consistent temperature of 75C.

Food dehydrator.

The problem is the assumption that people will consistently manage to ensure it only reaches 75 degrees.

Ironing clothes is 100-250 °C.

Should we just be ironing masks?

I'm confused by all the disclaimers regarding home ovens. WHY NOT a home oven, what is the scientific reason? I've been baking N95s on a tray in our kitchen oven at 170F for ~20-30 min and reusing. These articles seem to suggest that's a bad idea but do not say WHY. Would love to know WHY.

Perhaps just because of the step where you bring the contaminated N95 into your home kitchen and handle it there, before it enters the oven? This sounds tricky to get right.

Do we need the steam bags to pack the n95 respirators? Or is it okay to just put inside the oven.

TIL U+2103 DEGREE CELSIUS and U+2109 DEGREE FAHRENHEIT.

It took me a few passes to realize you were not just being comically excited and typing in all caps, but rather, everything you typed is rather pedantically and accurately capitalized.

I just copied the DuckDuckGo Unicode Instant Answer (https://duck.co/ia/view/unicode) ;)

On Windows ALT+248 (on keypad) makes a degree symbol: °

IMO it looks better than the single glyph. (°C °F vs ℃ ℉)

Unicode agrees:

> Several letterlike symbols are used to indicate units. In most cases, however, such as for SI units (Système International), the use of regular letters or other symbols is preferred.

> In normal use, it is better to represent degrees Celsius “°C” with a sequence of U+00B0 degree sign + U+0043 latin capital letter c, rather than U+2103 degree celsius. For searching, treat these two sequences as identical. Similarly, the sequence U+00B0 degree sign + U+0046 latin capital letter f is preferred over U+2109 degree fahrenheit, and those two sequences should be treated as identical for searching.

(From https://www.unicode.org/versions/Unicode13.0.0/ch22.pdf)

The why include the symbols in the first place? Just in case?

It's most likely for round-trip compatibility with another encoding. There are many Unicode codepoints that simply represent combinations of other codepoints. If you don't care about round-tripping, just normalize everything to NFKC or NFKD (the difference being that accented letters like á are one codepoint in NFKC and two codepoints for the base letter and combining mark in NFKD).

For lossless round-tripping with legacy character sets. This is one explicit design goal of Unicode.

So we can make search that tiny bit more complicated.

Does that not appear correctly on your device? Which would that be?

No, it does (a bit squashed, but it's perfectly readable). I didn't know there was as specific Unicode character for those.

As a rule you can just assume there is, no matter the situation.

if you're on a Mac, you can use alt-0 for a degrees symbol too

That's actually U+00BA MASCULINE ORDINAL INDICATOR. You want U+00B0 DEGREE SIGN, which is ⌥⇧8.

Upvoted as one of the most HN comments I’ve ever seen.

I’m generally amused that a top thread for an N95 sterilization post is a Unicode discussion.

What’s the feminine ordinal indicator. I thought it was a degree sign because as a Portuguese speaker I’ve never noticed the feminine ordinal indicator as an easily accessible option. Are both easily accessible on the iOS keyboard?

U+00AA FEMININE ORDINAL INDICATOR is ª, accessible via ⌥9 on macOS.

I just realized I have used the ordinal symbol many times when I should have used the degree sign. Why didn't someone tell me? Oh, I've been making an idiot out of myself.

That depends on the keyboard layout. On the Norwegian keyboard for example, ⌥⇧Q produces the degree symbol, whereas ⌥⇧8 produces U+007B LEFT CURLY BRACKET.

You totally blew my mind—I've been using the wrong one for years. Henceforth, ⌥⇧8. Thank you.