If you are healthy, there is no need to wear. But I understand some people are still very panicky and worried so you can try this to prolong your mask life so those who really need masks can get them. This guide is translated from a live event organised by Singapore Press to aid donation funds to Singapore Red Cross to help at Wuhan.
The advises are given by Dr. Leong Hoe Nam (Infectious Disease Specialist at Mount Elizabeth Novena Hospital). Usually disposal masks are only to be used once and disposed. However because we are facing global shortage, so those healthy ones who are still worried and still insist to wear can try. Full video: https://www.zaobao.com.sg/livestream/project/story20200209-1027124 (01:00:00)
This is alike to disposing your um, sanitary napkins... which one of my readers pointed out :P