Whichever pattern you use, you should consider how your mask can be cleaned. After all, it takes a few hours of wearing for it to become warm and humid, being the dream environment for viruses and bacteria to settle in. That's why regular cotton is a good choice – you can just put it in soapy water (dish soap, hand soap or laundry detergent – all will do) for a few minutes, wash and rinse. Having more than one mask is a good idea to switch between the two and allow one to dry.
Things to also keep in mind: if you're using a pattern that includes room for filter (like paper towel or coffee filter), you should dispose of it after every use. And then there's taking the mask off after use: always presume it's infected with something and be very wary of what you touch with your hands after touching/removing your mask. Extra hand washing afterwards, as well as disinfection of all surfaces you've touched is highly recommended.
Mask patterns by Masks4All.co and the CDC
