LA-based artist Allison Cortson creates portraits using dust she collects from her subject’s vacuum cleaner bags.
From New American Paintings #79:
For these portraits, I photograph the subjects in their homes. Then over a period of months I collect the dust from their vacuum bags. .. The paintings are completed by rendering the subjects life-size in a realistic manner in oil; the rest of their environments are created solely out of the dust collected from thier homes. In my experience I have found that every person’s dust is a different shade — subtle, but you can see it reflected in the finished piece.
Screenshot from the artist’s website