How did 革 get the meaning "change" 變革？ I wondered how a character originally representing animal skin could appear in words such as 沿革、革命、變革. 
Ripping off the skin from an animal, thereby "removing the old and getting the new" seems a little far-fetched.
Or was there just a mechanism as profane as sound loan at work?

All ideas are much appreciated!
说文解字:


  革、更也。二字雙聲。治去其毛。是更改之義。故引伸爲凡更新之用。


According to 说文解字, that is truely how it works.