In reply to bonebag:
The normal checks are to feel your ways along the rope to feel for soft spots and roll a loop passed the damaged part to see if the radius of the loop changes at the potential damaged part. If the rope folds sharply at the damaged part and or feels soft at the damaged part then it's certain there is core damage and you should chop it.
If you do chop it be sure to re-mark the centres (if you have centre marks) to avoid confusion if you or a friend is setting up an abseil on a single rope and better still always tie knots in the rope ends/get your second to tie in if multi pitching.
It's crazy how many accidents are reported to Rock+Ice related to abbing off/lowering people off the ends of a rope.