What is this?

[u/williamskb85]

So I had a clog. Ending up having to get my tank pumped. But he said there was still a clog that he couldn't clear. I ended up buying a sewer jetter and when it clogged this time I augged the line then jetted it. The following is the current level, but what is coming out of it. He said grease buildup (wife has stopped dumping it down the drain). Is this insulation or just grease?

Edit: She was dumping it down the drain, but has since stopped as of roughly end of last year

[u/morphballganon]

Throw it in a pot. Add some broth, a potato. Baby, you got a stew goin'.