Yes just plain water, and it will do both (kill and contain).
As for the mother, I've never done it myself but - I think at another forum - some said they pollinate females by removing them from the closet, pollinate, wait for several hours, and then spray them down. By that time the pollen already did its job, and any that did not reach a pistil will be disabled. Then let it dry, and put it back with the rest. I'm always battling against high humidity and spraying down females during flowering is something I'll probably never do. Point is, yes spraying that mother wet will work just fine. If any exceptional pollen grain survives it probably deserves to make offspring
Edit: probably obvious but meant "did 'not' reach a pistil", i.e. the pollen on leaves.