Don't have any wear that looks like smudges. Altough the glossiness has somewhat worn off and its starting to look more matte.

You could try wiping it with strong ethanol. That should be pretty good for dissolving organic smudges. The plastics seems to be ethanol resistant, or at least it didn't get damaged after I used paper towel soaked in 70% ethanol to sterilise it after a lab accident that involved getting bit of liquid bacterial culture on my phone.