In reply to philmcf:
If it's only small you can probably just beat it flat with the spine of another krab.
Worse (but still small) nicks can be filed smooth with a small half-round file, just go lightly and don't cut too deep, it only has to feel smooth, not perfect. If you're really careful the rectangular file in most combi-tool knives can also be used but you do need to be gentle to get a good finish!
jk