I've used a Dremel many times to clean up tube pins, it's not difficult at all as long as you pay attention to the direction of tool rotation and use it correctly. I use Maas metal polish on a small felt wheel as opposed to the brass brush though. Even if a pin gets bent a little, a quick tweak with a pair of needle nose pliers gets them back in order. Then clean the residue off with alcohol like the previous post describes. I also have used the exact same procedure described above with the exception of using very fine grit wet or dry sandpaper strips cut 1/4" wide instead of a polishing cloth. Usually 1000 grit works fine.
polishing pins of NOS tubes
I have some NOS tubes with corroded pins. I read that you can use a short brass brush to polish them. You can even attach a brass brush attachment to a dremel and spin it, but that would be a bad idea for me as I'm very clumsy and would most likely bend the pins.
So I ordered some short brass brushes from Amazon and gave it a go. There was essentially no corrosion removed after brushing one pin for 10 minutes.
The set includes a steel brush. I brushed a couple pins with that for 5 minutes and they got shiny! However I'm wondering if this can scratch the pin and actually degrade performance of the tube.
Anyone have a recommendation?