ask for restore technique

[Ducthang201k]

Finally i got one from an other owner, but it seem quite old, the button and the shell is stained abit, so is there anyway to "clean" it? , especially the buttons

 

[OldSchoolVPQ]

That level of dirt should come off with rubbing alcohol on a cotton swab. I use the purest ethanol available at the pharmacy. Careful near the paint, though!
For the button area I would use a toothpick to gently scrape at the indentation after lightly soaking the tip in the ethanol.