Remove dirty/sweaty hand prints from painted wall

Sometimes while I am working, I inevitably end up touching recently painted walls with my hands. Though I try to keep my hands clean, the combination of the dirt and sweat on my hands leaves a very visible brown smudge on the wall.

I do not know what type of paint is used on the walls. The paint has had 24 hours to dry, but it typically has been applied within the past week.

What is the best way to remove the smudge? I would rather not carry around a spray bottle with soap water and clean rags. Would lightly sanding the spot with a very fine grit sandpaper work to remove it?