I had someone ask me yesterday if I knew of a lab that could handle a volume of "head clips." Unfortunately, I didn't have a chance to ask him what he meant.
I've never heard that phrase before (and it didn't come up in the google search here or on the web).
I know of a "clip test" whereby a few frames of film are sliced off and developed as usual. Any development corrections (push pull, maybe color shift) can be ascertained by analysing the results.