I found something else in the loft - Vermiculite

[Deleted member 174758]

Amazed it survives the w/mc. I think I might pass on that one for now. . . . .

Well, it is only the mask, NOT the filters, so not really surprising TBH - so long as you have it on a 30 degree wash

Looking at the pictures of Keith's masks I'm wondering if the filters in these masks are a bit on the small side for you commercial guys. . .

They are actually OK (more filter area than the 3M masks I used to use) - you also have to remember that we are supposed to run dust collecting kit on a vacuum as well, so the filters aren't worked that hard

Absolutely the worst contiminant I've found for filters on masks and in vacuums is soot - because it contails all sorts of sticky resins and tars