I've been using BACO'S bore cleaning system and it has been Excellent. However I have noticed a number of the felts getting "spongey" and losing density and size. I have been cleaning them in water, detergent and Oxyclean to get them clean as I read here or elsewhere that worked well and it does. However I was curious about them deteriorating and checked about cleaning wool which I understand from what I believe is the composition of the felt cleaners. Oxyclean isn't recommended for wool as it has an alkaline base and wool is slightly acidic. I haven't proved it is an issue, just a precaution at this time.