That virus would not live very long on them. Packages and parcels are safe.

I mean, they can add it, I suppose, but it won't be all that effective, unless they really slow things down.

Now ethylene oxide, maybe... (no, infrastructure not there)

https://www.worldometers.info/coronavirus/

The special handling delays their arrival.

https://www.washingtonpost.com/politics/ten-years-after-anthrax-how-safe-is-your-mail/2011/10/12/gIQAR8BadM_story.html

It's the process put in place after the anthrax attack in 2001, but I wouldn't count on the biohazard machines. Reason? After that process, many people will still handle your mail before it gets to you, namely station clerks and letter carriers, and there is no detection for what viruses or other bugs they might have that transfers to the mail.

So I would go with what the CDC or WHO says about how long the virus is active on paper. If you're at high-risk, you might want to wear nitrile gloves while picking up mail and put it in a safe space until it can "decontaminate," probably a day or two. Then open it once the danger period has passed.

You'll want to do this because most postal workers don't wear gloves or masks when they handle mail. It's not because they want to harm you, but because the work makes gloves and masks inconvenient. The gloves can make it difficult to sort individual pieces of mail when you need to; the masks can cause heat exhaustion. Trying to breathe through a mask when you're during hard physical labor is no fun. So it was rare to see anyone using the masks. Gloves, most of us did use. I did because handling paper all day dried out my skin too much if I didn't, and I hated how dirty the mail made my hands, too. But not everyone is that finicky about their hands.

The point is that whatever is on the hands of the postal workers handling your mail will get on that mail. If they sneeze or cough, it will get on your mail. Especially at the station and through the letter carrier, often within that 24 hour window you need for safety. That's why you pick up the mail wearing gloves and open it after the virus dies off on the paper or cardboard. Or open your mail with gloves on, if you absolutely must get to the contents right away.

I'm going off my memory, so take this with a grain of salt, but I think you may be confusing different types of UV lamps. UV lamps are categorized by bandwidth, e.g. UV-A, UV-B, etc..

UV-C lights/lamps are used for their germicidal properties. I am almost positive that "regular" blacklights, the type you use to make your Spencer Gift's posters glow, use either UV-A or UV-B.

I realize that you're talking about use by the Post Office, but readers might decide to use inappropriate blacklights for personal sanitizing purposes, based on the info in your post.

I'm a bit short on time, but will try to find some harder information / citations later today.

I wonder if you can get one of those to put your cash and other items in to kill the gems.