Everywhere you go, there is a shortage of medical masks.  Even hospitals are running out of masks.  Hillary lead a team of students to make DIY disposable masks for friends and families, and for health care workers during emergencies.  The instruction can be downloaded HERE

Cloth masks may be more dangerous than disposable masks.  according to a report published by the British Medical Journal.  Disposable is the way to go.

The FuseBreakers MASK uses materials readily available.  Can skip the filter step to save cost.

4/3/2020 Update
CDC just recommended everyone to wear a mask   

Current CDC guideline on masks ​
Disclaimer: This is not a federally approved medical device. It is not intended to replace a medical device.

HCP Use of homemade masks:

In settings where facemasks are not available, HCO might use homemade masks (e., bandana, scarf) for the care of patients with COVID-19 as a last resort. However, homemade masks are not considered PPE, since their capability to protect HCP is unknown. Caution should be exercised when considering this option. Home made masks should ideally be used in combination with a face shield that covers the entire front and sides of the face.