Thank you for responding!
I guess I should have said: the isomalt I'm working with isn't covered in icing or anything . Question was more about the unavoidable smudges that happen despite careful handling.
I tried oil and for my purposes it seemed to work fine. That is -- temporary was fine here, just wanted to make sure the isomalt was clear as it could be for a photo. Random streaks of (in this case) white gel were driving me crazy.
Thank you! I sure like isomalt, so stable.