Came across this today. I remember there's been some talk on here about neck gaiters/sleeves. With a new study released by Duke just a few days ago, it's been found that neck gaiters/sleeves are actually worse than wearing no mask at all. Apparently allows all particles through, but breaks them up creating even more particles than if you were wearing no mask at all.

Perhaps the most surprising finding in the new study was what happened with neck fleeces, the coverings that runners sometimes use. When someone wore the fleece, the number of droplets was actually higher than if they wore no mask at all. The researchers believe that the material breaks larger droplets into smaller particles. “Of course, what makes that problematic is that smaller particles could actually be carried away with air much more easily than big particles that might just drop down to the floor,” Fischer says.

Cotton masks were effective, but bandanas didn't do much at all. I've linked the article and you can find the full study if you search.