[R-390] Cleaning tube sockets

[Dave Maples]

All: As is always the case, this group is absolutely invaluable in their
insight.  I've got another question.

I am repairing another R-390A for another fellow, and have run into TWO tube
sockets in the IF deck that seem to have "intermittent" pins.  Everything is
soldered; the receiver has sat for so long unattended, though, that the pins
themselves seem to have oxidized.

Suggestions?  Is there something I can use to gently clean the contacts in
the tube sockets?

Thanks,
Dave WB4FUR