Let's talk - door hinge DUST. I have white trim, and the door hinges leave an unwelcome dark dust that not only gets on the trim, but also, gets on the floor, leaving marks on the carpet. These marks on the carpet are not easy to get off light-colored carpet!
It's caused by the rubbing together of the hinge parts. Microscopic pieces of the metallic coating plus dirt and lubricating oil combined to produce that nasty residue that eventually falls to the floor. You will see this happening on the most used doors - front and back door, bathrooms, etc.
So, what can you do to keep the hinges from making these marks?
You can minimize it by removing the hinge pins and then the door from its opening. Next, wipe down the hinge leaves and pin with some mineral spirits. Reinstall the door and don't lubricate it unless it squeaks.
If a door is especially squeaky, you can spray a Teflon-based product or try the new dry lubricating spray by Elmer's glue.
To clean the carpet, treat it like a greasy residue stain, and hope for the best. The baseboards and trim can be wiped off with Goof Off.