The gunk that collects at the bottom of a refrigerator after years of not cleaning it.
Any gunk that you can't really describe and you don't know what was used to make it or where it came from.
The remnants of lint from underwear in your butt crack.
I have to go clean the scabage out of my refrigerator.
I have to remove the scabage from between my toes.
What is that scabage hanging from your nose!
Ever seen scabage like this?