The CDC has stated that if no manufactured masks are available, that homemade masks such as bandanas or scarves may be used as a last resort. Although, there have not been studies done to see whether these are effective.
More recently, as hospitals and healthcare workers experience shortages of personal protective equipment, calls are going out for community volunteers to sew face fabric, reusable masks. There are several websites with patterns and directions, and studies have been conducted comparing DIY mask materials with vacuum cleaner bags, pillowcase fabric, and 100% cotton t-shirt material most protective, though not as protective as a commercial N95 mask.
Drafted 1 April 2020