Emil is my "yup this is real wool" detector. It's only real wool that he goes this nuts over
Cats fucking love lanolin (naturally occurring on sheep's wool, secreted by their skin) so it's possible that whatever brand of wool you buy doesn't strip all the lanolin off during processing. The majority of wools will have as much stripped out as possible but it depends on what you buy and where/how it was processed.
I think they particularly love it from the source...








