My two cents are that anything you can learn to take apart and confidently clean and reassemble fits the bill.
WHich brings up the subject of the smallest possible cleaning kit.
To me, the smallest possible cleaning kit would be:
1) Bore snake of the right size.
2) Toothbrush
3) Bottle of combined cleaner/oil
4) Scavenge some rags
Any better ideas for the smallest possible kit?