In order to avoid (cross) contamination and spreading of the virus, it is important to use, wear and dispose of those disposable masks in the correct way.
The World Health Organisation (WHO) has an excellent page that explains when and how to correct wear and dispose of a mask, we encourage everyone to read it before using disposals masks:
When and how to use masks !Disposable masks are single-use products, so once used they should be disposed of in the proper way and not re-used
The incorrect use of a mask might hamper its effectiveness to reduce risk of transmission.
With the current shortage of disposable masks and the priority given to supply hospitals, medical centres and healthcare professionals, we have witnessed an appeal to companies, organisations and the general public to produce masks to help the health care workers to protect themselves. This obviously with the best intentions in mind.