DeoxIT on tube pins

for tube pins.. use Caig Gold Dx2/ different than the regular gold 100L The Dx2 is good up to 500C temperature!!! cost a lot more though.   like   $99.                     
https://www.amazon.com/DeoxITGOLD-Liquid-brush-appl-Tracer/dp/B003D8GUAA

I have only ever used a simple soft erarser to clean the pins. Simply push the pins into the eraser a couple times . You can see the black it leaves behind and inserting them back in snug sockets will finish a clean contact. Pencils with eraser tips work well on the smaller pins . No need for chemicals or especially risking sanding off, or through plating either. Seams more like seeking a problem or creating one than needing a solution. 

0000 steel wool works great on old tube pins.  Not as aggressive as grit but better than a magic eraser for me.