Re: Problem with door hinges
The powder could be graphite, though I suspect it's just hinge wear.
Try a little bit of lighter fluid, the kind used in Zippo lighters, on a soft cloth and test in an inconspicuous place. If the debris comes off without any damage to the finish, then you're good to do all your hinges this way.
Prevention ... Use a silicone lubricant on the hinge pin and fingers of the hinge. Lubrication will reduce/eliminate wear. Don't over lubricate or you will get drips and runs. A couple of drops is usually all it takes.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!