[Harp-L] oil on your skin will cause premature failure" [of tubes]

[BluzeHarp@xxxxxxx]

Is this true?  "oil on your skin will cause premature failure"  [of tubes]
 
I used to install and repair industrial bake ovens that  utilized high 
intensity halogen lamps.  These bulbs run much hotter surface  temps than vacuum 
tubes, oils from your fingers via clean hands would  cook on them and cause 
them to fail.  The handling practice was to not  touch them directly, and 
to wipe them with alcohol before & after  installation.  
 
With that in mind, several years ago I asked an amp builder  the same 
question about tubes.  This is a guy  who supervises a crew that designs 
electronic circuitry, he's  also a tube amp builder and ham radio enthusiast... I 
trust his  advice.  He told me that amp tubes don't generally get hot enough  
on the surface for normal oil transfers from clean hands to have an  effect. 
 That said, I think if your hands aren't clean, or if the tube  has 
accumulated grime from other sources then you could trap some heat  & cause a 
problem.  Store properly and wash your hands before  handling & you should be ok. 
 If in doubt wipe your hands and the  tube with alcohol, but... be aware 
that could remove the  factory markings from the tubes, some of the expensive 
vintage ones  are especially susceptible to this.  Keep tubes free of dust  
accumulation, heavy dust buildup can trap heat and shorten life.   Keep 
spares well padded and in their boxes.
 
The other end of the tube often gets mistreated.  Pins should be clean  
(again alcohol is good, better if it's 91%) and straight before a tube goes  
into it's socket.  Sockets should be clean and undamaged, especially  
important to check this if you've had a tube failure.  Avoid a  lot of wiggling when 
removing or installing tubes, push as straight in  and pull as straight out 
as possible.  
 
Christopher Richards
Twin Tone Harmonica Microphones  -  harmonicaplanet.com