It's probably been more than 25 years since I fooled around with
8-track tape cartridges, but I still remember a few things.  I actually
had an 8-track tape recorder, and used to record music so my dad could
listen in his car while driving to work.

Clean the capstan roller in the tape deck.  Sometimes they get dirty or
sticky, and that will cause them to eat the tape.

Assuming that you have extricated the tape, open the cartridge.  There
will probably be multiple twists in the tape.  You will have to cut the
tape near the point where it exits from the center of the spool.  It's
then a simple matter to rewind (by hand) the tape onto outside of the
spool, taking care not to tighten the winding.  You want the spool of
tape to be loose enough to be able to be drawn out of the center
without binding.  It's then a simple matter to splice the tape back
together and reassemble the cartridge.

Mark Pleatman  (My first post to MMD!)