[K7Sparky]

In the way back machine we used to reglue the bases fairly often. The old brown glue came loose and I have been trying to remember what the "Old Timers" of the 60s had us using for cement. Might have been water glass. Might try Google.

Some times we soaked the bases loose, desoldered the pins and put back together to get a different configuration or separate wires if multiple elements were on one pin. Don't remember what the tubes we soaked were or what we were reconnecting. Some brands were possible others hooked inside the bottle. Probably for a low power transmitter. Also some tubes were the same as others except the pin out.

Don't know where you live, but try to find a local ham club or Maker group. Someone may have a tube tester and help you out.

A tester will give you a good indication that the tube will work, but the only way to know is try it. If you have ones with the same numbers they may work if swapped.

As Codefox says use a sitcker or a sharpie to label the base as the numbers and letters dissapead easily.

If they are hard to read, cool the tube if necessary and a slow breath out of the mouth on the bottle to fog it will sometimes help bring out the writing.