I once back dusted a rug for a client, she was really worried as it had been in storage and she wanted it cleaned.
Having back dusted I knocked at least a couple of kilos of white powder out of it,
I jokingly said you must have some great parties.
She came back an hour later, I have just realised what it is she said.
20 years of shake n vac.... I offered to refill her old bottle back up.