Many thanks to both of you (David and Shaggy) for your replies. Yes, the holders do disassemble by removing four screws to access the light trapping end. It's a little tricky to remove the felt. However, what a great design for strength, longevity, and reliability these holders have. The felt can literally be turned over, end-for-end, reinstalled, and the holder should be good to go. The spring design is quite interesting. It's a strip of (comb-like) brass that seems to have maintained its tensile strength. Thanks again, folks!