After a little researching i believe this powder is a graphite powder lubricant to help the hinges operate smoothly.
How to remove graphite from door hinges.
Use the vacuum hose only with no additional application.
Clean the flat surface areas.
Do one at a time completely.
Take pin out of hinge and put all parts in a small dish with boiling water with dish detergent and let sit.
Find this pin and more on good ideasby vicki jaeger.
We say try using a magic eraser on the hinges.
This will simply spread it around.
Next wipe down the hinge leaves and pin with some mineral spirits.
Put on a pair of vinyl gloves and wet a rag with rubbing alcohol.
First remove the hinge pins and then the door from its opening.
After you have removed as much graphite as possible by vacuuming you can move on to step number two.
Remove the door and clean the hinges and hinge pins with rubbing alcohol.
Place a drop cloth or a newspaper below the hinges to catch any graphite dust.
Do not make the mistake of just running your vacuum over the spot.
I made the mistake of spraying wf40 on hinges and paid for it.
We built our house almost 5 years ago and in that time a film of black powder has built up on the door wall and baseboards around all the door hinges in the house.
No quick cure but this worked best for me.
Reinstall the door and don t lubricate it unless it squeaks.
Take one hinge off door and clean area with a detergent.
It s also great for remove dried latex paint off of trimwork.
To remove graphite the black powder around door hinges inside the house use krud kutter.