Surging coronavirus cases in the United States, driven by the highly contagious omicron variant, have prompted renewed recommendations from health experts that the public should consider wearing more protective face coverings, such as N95 or KN95 masks. 

President Joe Biden also said his administration is working on making such higher-quality masks more widely available.

"Next week, we'll announce how we are making high-quality masks available to the American people for free," Biden said Thursday. "I know we all wish that we could finally be done with wearing masks. I get it. But they are a really important tool to stop the spread, especially of the highly transmittable omicron variant."

The administration noted this week that the Centers for Disease Control and Prevention "recommends Americans wear a well-fitting mask." Biden acknowledged Thursday that "for some Americans, the mask is not always affordable or convenient to get."

Health experts say while there are no hard and fast rules, there are best practices for safely getting multiple uses out of N95s or KN95s.

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How many times can I reuse my mask?

"In the ideal world - or pre-pandemic - many masks were really viewed as single-use," said Michael Knight, an assistant professor of medicine at George Washington University. "The reality is they do have a little bit more length in the amount of time we can use them."

What's crucial, Knight said, is making sure the mask has "maintained its integrity." Think about how many times you've used it and for how long, he said.

"If I'm just putting a mask on to go to the grocery store for 45 minutes and I'm taking it off, that mask very well should be able to last me a couple of days," he said.

But if you're wearing a mask all day, such as during a long work shift where you may be sweating and talking all day to the point the mask becomes soiled, "then that may not be a mask that I can reuse."

"If I'm wearing it for three hours, I'm going for a workout and I'm sweating, then that mask is most likely going to be soiled," Knight said.

When you start seeing signs that the mask is soiled, "you're getting to the point that that mask needs to be replaced," he added.

Even with normal use, if you wear a mask for a few hours a day, "within four or five days, it's going to be visibly soiled," Knight said.

The CDC website notes that it recommends using N95 respirators for no more than five uses.

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What are some best practices for safely reusing my mask?

Some experts suggest having a few masks on hand so you can rotate between them. That way, after wearing one mask, you can set it aside for a few days before picking it up again, said Richard Carpiano, a public health scientist and sociologist at the University of California in Riverside.

That would allow "enough time for any sort of virus particulates or virus remnants to die off," he said.

The reason to have a rest period between uses is to let the mask dry out and to give time for any viral particles the mask may have filtered to deactivate, Knight added. He recommended resting your mask for 24 to 48 hours.

But don't keep the masks in rotation indefinitely. After a few wearings, "you want to move on to a fresh one," Carpiano said.

Knight has stressed that people should wash and sanitize their hands after taking off a mask and recommended removing the mask from the ear loops or elastic bands to avoid touching the outside of the mask that may be contaminated.

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Where should I store masks between uses?

The key is to keep the masks somewhere where they can air out, said Christopher Sulmonte, project administrator for the Johns Hopkins biocontainment unit.

"There's going to be a little amount of moisture on the mask itself - that's just naturally what happens when you wear it," he said. "Having a space that you're able to dry it out is important."

Sulmonte recommended placing the masks in a paper bag, because it's a clean place to keep the mask and it's "contained enough that you can still have the process of letting it dry out."

Knight recommended a mesh bag as another option, placing it "somewhere that air is flowing."

Storing your mask in a clean place where it can dry out will prevent it from being exposed to contaminants between uses and will prolong its effectiveness, experts say.

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How do I know when it's time to throw out my mask?

Examine your mask and determine whether it's safe to use based on two main factors, Knight said: the mask's condition and fit.

If the mask has a cut or tear, it's no longer usable, Knight said.

The mask should also no longer be used if it's "severely soiled," he added.

If someone was sneezing while wearing the mask and "mucus has now infiltrated the mask, that mask is soiled and they can't be used anymore."

There's also a difference, Knight said, between a mask that has moisture from normal use or one that has been "saturated."

"If you have a mask on and you're talking, there are microdroplets, because our breath has moisture," he said. "So of course, there's going to be some low levels of moisture."

That's why it helps to air out the mask between uses.

"But if the mask is saturated from some fluids, that's a different story," he said, perhaps from saliva or maybe you were caught in the rain and the mask is soaked with water.

Then it's time for a new one.

A mask that is saturated is compromised, Knight has told The Post.

Experts note that KN95s and N95s - unlike the cloth variety - cannot be effectively sanitized by standard washing.

The fit is also crucial.

When you notice the mask no longer seals well around your nose and around your face, "maybe the nose band is not as flexible and you're noticing there's a gap ... that's the time you want to discard that," Carpiano said.

For N95s specifically, experts underlined those are most effective when they are fit-tested, because they need to press tightly against your face and form a seal.

Over time, the elastic keeping the mask in place can stretch.

"If that fit is no longer tight and no longer forming a seal, then that mask is no longer as effective in filtering the air you're breathing," Knight said about the N95s.