js3830

I bought a Singer 99 at a thrift store. I am cleaning out the lint and oiling it. A lot of lint but in real good shape. When I started to clean the bobbin area there is a red piece that I throught was thread but when I pulled on it I knew it wasn't thread. It is more like felt and it is looks like it is stuck in a spring so I left it along. Is this the right thing to do? Thank you, Sandy