That’s why Deoxit for example is safe to use on tube pins. That’s also why commercial aircraft use it on communications electronics.
How much heat are you talking about? What's the voltage?
Here is the typical statement found in an ARC owners manual for tube audio equipment.
//
Quote:
"3. Note: In general, contact enhancers are not
recommend for use on vacuum tube contact
pins. With continual exposure to heat and air,
many of these substances can form gummy, dustcollecting
residues which actually reduce
contact and degrade sonic performance. Proper
external use of these preparations – on
interconnect plugs, speaker connections, etc.– is
subject to the discretion of the owner. Contact
Audio Research for specific recommendations."
End of quote.
//
I bet other tube equipment manufactures have the same statement in their manuals.
You can clean contact enhancers off of tube pins fairly easily. Not so easy out of the female contacts of tube sockets.
I'll just stick with using Isopropyl alcohol for cleaning tube pins and tube sockets.