Exactly, it's that lack of shedding that makes all the difference (and saves so much headache). The old wool just wears down slowly, getting softer but still working, while a plastic brush throws bristles into the flue from day one. Then you're just chasing bits of debris, and the brush gets wrecked way faster. It's a buy-once kind of tool, even if the upfront cost felt bigger back then. You hardly ever see them on shelves now, which is a real shame.