An old laser printer, unused for months and stored in the loft, didn't print properly when pressed back into service. I guessed the toner had got damp, and figured I'd hoover it all out and replace with new toner.
Job done, I thought, after a couple of minutes with an Earlex combi-vac, until I turned around to see the super-fine toner had passed right through the filter and out of the exhaust port, forming a perfectly circular black nipple on the kitchen unit door behind me, surrounded by a perfectly graded grey-scale aureole of toner over the entire wall. There was even a cat shaped silhouette on the window courtesy of my (originally pure white) Persian audience.
(The chapter entitled "I've bathed the cat, you pillock, pass the plasters", has been omitted for brevity).
Suffice it to say that the kitchen is now gleaming like a new pin, neither the cat nor the wife are speaking to me, and I'm now absolutely aware of the price of a new toner cartridge, compared to the cost of vertical blinds.
The printer works fine though ....