[Boatanchors] tube markings

[Troglodite at aol.com]

Regarding the fragility of tube markings - in many cases this was  
deliberate. During the heyday of vacuum tubes and especially up through the mid  50's, 
there were many tube rebranders, recyclers and rejuvinators. They passed  of 
their wares as new, because if a tube is clean, it's hard to tell it's age.  The 
numbers came off if the tube was cleaned, and this supposedly prevented  
resale as a new tube.
 
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The practice of marking the outside with a low grade paint has always  seemed 
to be a frought method of identification.

As this probably might  be considered to be a bit wide of topic for the 
reflector, if it is considered  to be then my apologies in advance (but I would 
still like to know !)