Large bandanna that is multiple use from dust mask to sling or bandage for injury.<<<
The cowboys also used them for strainers, as in bugs and crud out of water....
LOL, when I was young, I thought those red bandanas were for hankerchiefs and kept buying them for men, how was I to know that yankee men use white ones, that are too small for lots of uses.
Dr. Bill Wattenberg says that a wet t-shirt, or even your shorts, will protect you to a large amount from bio hazards that are blowing in the breeze or falling from the air.
Yep I use em for same reasons and also on a plane where I can’t carry a knife or my pistol. I have a small pocket sewn into the corner that I put an unopened roll of quarters or twon in and use that for situations till I get back to my checked baggage with gun and knife......:o)
many many uses for the bandannas......one I carry every day has a small 550 parachute cord sewn into the edges as well as the above mentioned “coin purse” pocket so I can use the bandanna as a drawstring bag if needed also. For collecting berries and other found sources of food in the wild.
When prepping water for a filter or boil I use the bandanna as a pre filter as you suggest as well.
Also carry a neon color four your bandanna of choice for signaling or even cutting off a very small piece to put on a fishing hook. Yep it works as bait too !......:o)
I had troops that would fold and iron the big ones and place em under their boot inserts so they always had spares.
Then there is always the magic tricks you can use it for where language is a barrier. Used many times in my military career to make locals smile and relax when they were scared etc ......
I also lay mine in the bottom of a dark stream with rocks securing it so I can see the fish swim by or over it and shock fish with a large rock...... stuns em just long enough to toss on the bank.
Many many uses....always have one with me !