Sludge

In science class at my kids' school they have a project called "Sludge".  Each student gets a jar full of unidentified material and the student performs various experiments to determine what components are in their mixture.

One of the sinks in the kids' bath has been draining slowly, so I took it apart today to see what the issue was.

It was sludge.

The tailpipe on the boys' sink was mostly clear.  The one on the girls was lined with this.

I'm not sure what it is really.  There's a little bit of hair in it, but it's mostly a thick layer of goop around the inside of the pipe.

Is it several years worth of makeup residue?