I've seen this same method from other DIY videos. Went quickly into Walmart a couple days ago and many people had homemade face masks on. I also saw a video to put a cut out from a furnace filter inside to make it even more protective.
"You stand between me and my lord and kin. Begone, if you be not deathless! For living or dark undead, I will smite you, if you touch him!"