Bought this item for use in our home improvement projects, painting, sanding and even taking out 60's vinyl which could have been possibly-- made of asbestos material.  It worked well, certainly kept dirt and smells away.  We used it to sand down drywall from our bathroom & after 2 days of sanding the filter was noticeably dirty and nearly clogged.  My husband ran his filters under running water and it seemed to help keep it clean in between uses.  I kept mine original- no cleaning other than wiping the outside of the mask.  I used it for the other projects for a few weeks and it seemed to work well despite the weeks of use.  The mask itself worked well, keeping dirt, smells and toxic stuff out but I would say that it is extremely uncomfortable.  The plastic, while it securely hugs your face is not the softest.  Also, it is heavy.  I can only keep it on for 30mins max and I have to take it off to give myself a rest.