From: Edward V. Phillips [SMTP:ed-at-alumni.caltech.edu]
Sent: Wednesday, April 15, 1998 2:25 PM
Subject: Re: induction heater
"Another old trick is to rub the printing on the tube behind ones ear so the oil
to the printing and make it visable. Dosen't stink as bad as the ammonia!
One which has always worked well for me is to stick the
tube in the refrigerator until it is cool, then breathe on it.
The markings usually show up as patterns in the moisture which
condenses on the tube.