Hey Doug... yeah, just hot water. Mind you, I have my hot water tank set on HOT, so, the water that comes out of there, sure feels like it came out of a kettle. Three shots of 10 mls each, and it doesn't come back, (I don't use a needle, so, I blast it everywhere
). Also, rather than dumping the whole rock in boiling water, why not just pull it out and use a BBQ lighter to burn the little S.O.B.?
Would it really come back from that?
Good luck.
Robert