Caig Pro Gold. Either use the pencil or put it on a small lint-free cloth and wipe the tube pins, then run the tube in and out of the socket a few times. You can use compressed air for dust and such.
The reason for the Pro Gold (which is, I think, actually more expensive than gold by weight) is that it is the only product I am aware of that will not turn to varnish when things heat up -- particularly for an amp that runs the tubes inverted.
Some sockets are not worth cleaning and should be replaced, like these from a '81 Deluxe Reverb.
(That's RTV in there... who needs tube clamps, eh?)
Thanks for the reply. I don't think the tube sockets are as bad as the ones in the picture you posted. I have some Cleaning Duster "Pressurized Air Duster" from Office Depot hopefully that will get the job done.
Not to be a di** but why ask the question if you are going to use the "air duster " you have to begin with?
Air in a can will not clean the tube socket or remove any oxidation.The Caig Pro gold that was recommended is a very good product.If you don't want to spend the bucks you can use some Caig DeOxit and save a little.