scanning E*ay adds for various electronic items.
 

While looking at the adds for parts, tubes etc, I came across a listing for two Genalex Gold Lion KT88's, used. The picture of the tubes showed a brown area around the getter flash.
Unless, I'm mistaken, that brown cast is an indication of the tubes were "red plating" or just plain "spent". I have an old Pilot stereo amp that uses EL34's. It's 60+YO and they have that same brown cast and I figured that they're way past their prime.
Any opinions?

Not necessarily:

https://tubesound.com/brown-or-black...not-mean-used/

:scratch2: jr

I've got some power tubes that are brown but work fine...My metric is if it tests fine and performance doesn't substantially improve if I sub in another good tube I leave the brown one in till it goes bad.

I'll use the tubes I presently have, but I will not pay the kind of money they're asking for questionable tubes.
When I was repairing TV's on a regular basis, I would see a 6LQ6 HO tube in that condition, it was usually near the end of it's life.