Sad news indeed. I knew him and the other Spinners for many years and always enjoyed the friendship. Cliff was great to talk to and as earier posted, his music added another dimension to the group repertoire. The Spinners were hugely influential, they spread the word of folk music to thousands of people who might not have heard it otherwise. I totally agree with the posting from Silas.
Goodbye and Rest in Peace Cliff. You leave many good memories behind you.