Freezing a Wart

So after working for a dermatologist when I was in college I learned that to get rid of a wart all you need is some "dust off", a funnel, and a bandaid. So you just turn the dust off upside down, center the funnel over the wart and spray the liquid nitrogin on it and let that effect it for 10 seconds. Then you cover with a bandaid until the blister heals. So we did this for Perry's wart he has been annoyed with since he had some scar tissue that turned into a wart on his face. So it didn't go as clean and easy as I planned lol. Perry numbed the area first, then held the funnel to his face while lying his head on the ottomon. Then I put the dust off (upside down) on the wart and I assumed it would all dissipate quickly like its supposed to. Well I guess there's not as much oxygen in the funnel and the liquid didn't dissipate. So the liquid was on his skin way longer than 10 seconds. Not knowing what to do I spilled some on my hand and Perry's from coming out of the  funnel, then I decided to go grab a towel and then I poured it out on the towel and it evaporated immediately. But then the funnel was stuck to his face lol. I put my fingers close to where the face met the funnel and eventually it warmed up enough to come off his face. He had the funnel sized lump on that spot and put a bandaid on it. Within a day it had become a blister and we will see in about a week if the wart is gone. If not round two and hopefully by then it will be gone. Anyway, lovely story huh? I found it quite entertaining. It makes me laugh when I think about it.