According to this film expert from the BBC,
you can make a whole movie on "scraps of film."
Hmm. I sure don't use "scraps." I use reloads and
recans and 35mm rolls that have been snip-tested.
They're cheap, but they're good.
I can make a whole feature movie that way too, because
I know where to get 35mm for nine cents a foot.
(Retail is fifty cents a foot.)
That's one of the most interesting bits of information to
be found on the "Independent Filmmaking CD Vol I" which
will set you back a buck, and you can find it here.