What's the best way to remove a sticker from a vacuum tube without damaging the tube? Is I true that if you scratch the glass, like with an Exacto knife, the tube could fail?

I purchased a quad set of audio output tubes for a stereo amp. The seller put an identifying sticker on each so it could be correlated to a piece of paper that shows their individual specs. After playing the amp for a few songs I noticed a burning smell. Immediately turned the amp off and realized the stickers are burning. Is this normal for tubes to get that hot? They weren't red plating and I've been monitoring the bias current to assure they are within range.

Thanks,
Dan

I am certainly not an expert here , but I know that the output tubes ,,49, 6V6 and 6F6 etc get quite hot, and I understand that it is normal.
If you don't want the labels on the tubes I suggest you use go gone ,or anything similar
product to remove labels.
Dan in Calgary

Thanks Chaz. I'm sure the temperature is normal but figured I'd ask.

I got the labels off like this: Using a Q-Tip, I dipped it in water and gently rolled it over the label until it was soaked. Then with my finger nail, I scrubbed it off. Then I used a Q-Tip with rubbing alcohol to get the remaining glue off. I stayed away from the original tube labeling, so they're all still visible.

I was cleaning a perfectly good 59 tube recently and used some steel wool to remove some stubborn dirt.

The next day I saw the getter was white!

There was a fine crack in the glass! I must have scored it and the atmospheric pressure caused it to crack....

-Steve

Ah, yeah, that's the kind of thing I was wondering about. With this amplifier I recapped, it was sitting in my garage for years. Mice got in there and well, there was some kind of residue on a few of the tubes, red in color. Probably blood. Mice are disgusting for sure. I scrapped the tubes off using an Exacto knife, very carefully mind you. Well, after recapping and playing it for a couple of hours, one of the output tubes went out. I don't think it had anything to do with scraping it with the knife. The filament still lights. It just doesn't pass any current from cathode to anode anymore. But since then, I read somewhere about a scratch on the glass could cause a tube to go out by either letting air in or some allowing some sort of impurity to get in there.

IF it was an old dried on sticker from decades ago, that could be harder to get off. I am surprised on a current tube that the heat of the tubes did not soften the adhesive enough to make them easy to peel off. I found isop alcohol can soak thru paper labels to soften the glue. Or maybe even denatured alcohol, a stronger solvent. I have even removed adhesive labels from a cardboard box with a heat gun. Get it pretty hot but not enough to discolor the box or burn it. The stick stuff softens up and you can usually peel it off as one big piece until it cools down too much.

I've found the best tape or sticker remover to be plain old Ronson lighter fluid (Naptha). Soak the label, wait a few minutes, peel it off.

Exactly!!! And the next step, if that doesn't work is denatured alcohol. One of the other will almost always work. White first aid tape seems to respond to alcohol quite nicely, even if it has been on, for instance a chassis, for decades. Patience is the key!

Ronsonol lighter fluid formula is changed since they were bought out by Zippo years ago, only 30% naphtha.
Coleman fuel is 100% naphtha.

You won't scratch the glass with an exacto knife. The glass is harder than the steel blade.

For something like this I typically use a single-edge razor blade and then cigarette lighter fluid to remove the adhesive residue.

RRM

Use WD-40. Apply to label and let soak for awhile. A slick surface label removal can be sped up by peeling off the surface and then applying WD-40. Some labels come off within minutes, others take several days. I just removed a label from a plastic zip top bag that was several years old. Only took three days and about 5 reapplications. Remove remaining glue and WD-40 with alcohol.