u/3magic4

I recently got my hands on a fleece and I have been working on washing a small sample. After washing photo three the tips were still pretty dirty and there was a yellow band in the wool. Once dry I flicked out the tips and it cleaned the tips pretty well (photo 4) but the yellow band is still present, I’m not super bothered by it but is it something that should be washing out or just a part of some the fleeces?