Scarves are probably the worst material to make a corona mask out of because it's so porous. Everything can get through it. If you want to make one yourself and want very good protection, use a bandana as your fabric to start with. Lay it open all the way. Then take a paper towel and lay it in the middle of the bandana. Then fold one side up and then the other. You will then have 3 layers of fabric plus the paper towel that you will be breathing through. I did a little research and I found that paper towels are one of the better filter materials for corona. So that plus the fabric and you're all set.On my local bus there was a poster stating you didn't have to wear a surgical mask. You could make one out of an old t shirt. Scarves etc is acceptable. The t shirt statement is actually mentioned on the poster.