national tv-7 set controls

[wiseguy]

i was bored today so i decided to start working on a national nctv-7 set, (i think that is the model)..all of the controls are frozen on it
and i decided to pop one of the rear covers off,odd.. these controls do not use a wiper against a resistive pad..but a ring that touches from a fiber wiper.and then the metal ring gently touches the resistive layer behind it ..looks like i will have to remove and clean old grease out of all of them..anyone else seen this?
i have never seen anything like it!!
here is a pic below..
also.. is anyone getting drnk this new-years eve..?
terry