FILTERED YET FLAWED

Casetify reusable cloth mask, £10, casetify.com reusable, washable cotton face mask with a pocket for a charcoal filter (also supplied). NUMBER OF COLONIES: 2 PERCENTAGE BLOCKED: 97 VERDICT: the five-layer filters are said to protect the wearer from pollen and pollution, but also claim to provide more protection for others if the wearer is infected.

the maker recommends replacing filters after seven days — a pack of ten costs £8. also, the masks are hand- wash only, so can’t be washed at 60c — the temperature considered best to ensure they are sterilised.