In ,
mike spewed forth:
Black foam is used as cushioning in equipment cases.
After some time, It disintegrates into an oily gunk.
What's a good way to clean up the mess?
Alcohol doesn't seem to help.
I'm afraid to get too aggressive with chemicals
cause I'd like to keep the outside plastic case intact.
Suggestions?

try WD 40, it will clean spray foam adhesive of your hands, so I would
think it would clean dead foam