I have a box and a bucket mostly of used tube . I was wondering if I should write on them but with what do I use they are some what faint to see! ? Also I was wondering what can be done about tubes that are not readable? I'm sure there area few of you could tell just by looking at them! I not you so should I just throw them away if not able to see numbers or what? I have a UTESTM tester that I got last weekend but it won't do the old 4 prong types like #80 #76 and the like. Is there a tube tester just for those old tube types that I look for? That's it Bill...Maine...

There are several ways to reveal the faded tube numbers, like white LED flashlites, breathing on the tube, putting them in the freezer for a few minutes etc.

I use a marker pen on mine.

Gee, 4 pinners are a breeze. The fat ones are the filament, and the other two are both plates, or if a triode, one of'em is the plate and one is the grid. Should be able to see what is going on easily enough. Any clue, like where it came from might narrow it down a bit. Pin 3 is almost always the grid and 2 is almost always the plate. Unless of course if it is a rectifier which would have two plates, pin 2 and 3. But, again you should be able to peer inside to check. You could probably check really conservatively as a triode using 1.0 volt heater current and your best guess as to which tube it is, and increase a little bit at a time until you get a bite.

You have rubbed a little n0se grease, then put in the freezer, and looked with a led flashlight (the newst fad!) an through the polarizer attachment of your defunct SLR against a flourescent light, and asked the grandchildren to have a look in the sunlight.

Post a picture here. Someone will pin it.

The most common permanent marker for glass is a Sharpie Industrial marker. It must say "industrial" or it's just the standard Sharpie ink like has been around for decades. The industrial ink was designed to write on laboratory glassware and stay on through harsh, high temperature cleaning cycles. It's tough stuff. You can buy the pens at any well-stocked place that sells pens and markers like an office supply store.

You should first clean the glass you're going to write on, of course.

• Super permanent black ink for industrial, laboratory and commercial use
• Ink resists most chemical washes and UV light
• Withstands extreme heat or steam (up to 500°F)
• Writes on metal, foil, glass, film and plastic

Hmm. Sharpie will rub off glass if it is handled very much, too. I have tried those label makers but being a curved surface, the labels eventually lift at the ends. Maybe putting them on the bases if they have one, and sealing the edges with something would prevent that.

Did you only see every third word of my post because you don't have your dime store readin' glasses on? I explained that these are not the regular Sharpies that every knows. They're the new industrial ink version of a Sharpie. The special new ink does not rub off glass.

Reading your post reminds me of Uncle Lewis in the movie National Lampoon's Christmas Vacation. I love that movie. Seen it?

May favorite scene: http://youtu.be/QEZWtohobaE

The guy in the Chair if he were younger could have been me back in the Day!Bill

I have had a few older tubes with masking tape on them with the tube number written in ink pen. I'd imagine some of them masking tape labels were 20+ years old, judging by the way the tape looked.

For locktals or any plastic based tube, just scratch the type number on the side of the base with a sharp pointed tool. Metal octals often already have the number impressed on the lower rim of the base.