Or "Wart Treatment using Liquid Nitrogen" as our clinical system would have it.
As an humble houseman it was my job, once a week, to book in around twenty patients on a Wednesday afternoon for "Cryosurgery" with a Consultant Oncologist. Some had skin cancers. Many did not. They had warts or Naevi (little red spots to those of you of a non-medical persuasion). They had all had to take half a day off work for the privilege. All had to be checked in by a gormless specimen just out of med school (yours truly), then get into a gown (no, really, they did) and go to an operating theatre for their "surgery".
The theatre had to have a nurse and an orderly to hand, and the Great Man Himself to do the "operation". Or in other words to squirt the offending body part with liquid nitrogen for anything up to thirty seconds. If you had a few spots treatment could last for whole minutes. Some patients needed fortnightly visits for a while to erradicate bigger blemishes.
For at least fifteen years we have had N2 here on tap. We have a special zappy flask for it to go in, with a great big trigger thingy. When you squeeze it Nitrogen zaps out with a fantastic hissy noise straight on to whatever you point the nozzle at. It's brilliant.
So now when our punters come in with a little annoying blemish we can zap them on the spot (geddit?) with no need for all that mucking about referring for "operations". An especially satisfying job for all concerned on a hot day. Plus you get to prance about the corridors with the flask zapping it in the general direction of the staff, PCT managers, the cat etc whilst shouting "Freeze!" in your best SAS impersonation. Even the older wiser partners have been known to walk about with it twitching the trigger to make a satisfying "puffer train" effect with clouds of vapour and a satisfying accoustic accompaniment from the nozzle.
As a generation of final year medical students will also attest, it's the most spectacular way to remove chewing gum from the surgery carpets.*
* Something they all get asked on their induction here. Please don't tell them though. It would spoil the fun!