So I was looking underneath my intake manifold and there seems to be a build of of some sort of fabric mixed with crumpled shreds of paper. I haven't removed it because I think it's some sort of insulation. There appears to be a smaller amount behind the alternator. Does anyone know what this stuff is? Is it junk?

 

Ya you have a mouse nest

 

Its a nest rodents made, no joke.

 

Lol I didn't think anything could live in there. It must have been sitting for a while before I bought it.