Stubborn set of Paddles!

OK... I've gotten pretty good at cleaning paddles. I've done my own set and a friends set. Both times with great success. My process is as follows:

Open up the paddles - remove the knob and the nut that holds the pot to the case and remove the pot from the case. Remove the metal sheath and pry open the 4 tabs to get at the innards of the pot and then spray with contact cleaner and gently wipe clean (usually lots of grime and black buildup). Reassemble (maybe give another squirt of contact cleaner after assembly) and play. Nice and clean and jitter free!

But I've just got hold of another pair (4 player Warlords rules!) that was in bad shape. But I'm a big believer in cleaning them to make them workable again but this pair did not clean up so well. I went through all the normal procedures for cleaning - and while it improved the paddles somewhat, both still exhibited some jitters that make playing less than fun. One was still parituclarly bad - so I opened it again and used a bit of high grade iso-alcholol and got it even cleaner - and then a quick squirt of contact cleaner... making sure to twist and turn the pot to really get it worked in. A slight improvement, but still jitters. I opened them a third time - lightly bent up the contacts and made sure the contact fingers were nice and aligned so that they would make better contact with the resistive material and that may have helped a tiny bit but still jitters (and now the resistance on the turn is slightly more than I like so I may undo that). Lastly, I opened them up and on the little metal contact fingers (which I'm always careful of since they look so fragile) I used the finest of fine sandpaper to lightly remove any oxidation that might have built up. And after all that there was little to no improvement over the first cleaning which did not restore them to "like new" condition that I've grown accustomed to from cleanings! I realize these pots are like 25 years old - but the contacts and resistive material should be pretty hardy - it's fairly basic stuff. But I'm guessing I'll have to replace the pot.

So... 2 questions.

1) Is there some way to coat the surface of the resistive surface to restore it somehow? Something other than just cleaning it? I assume a little electrical grease will do more harm than good.

2) If I have to replace the pot, is it as simple as finding a 1MOhm linear pot at Radio Shack? I checked the catalog - the one they have seems rather too tall for use in a paddle. Any suggestions on where to get one? Anyone got one?!

Thanks much in advance!