[bestgenman]

First, the coils in the automatic xfer switch are 120v not 12vdc.  There may be variations where the coils are 240v but definitely not 12vdc.  Disclaimer: I am not able to speak for the non-automatic switches but my bet is they are AC coils.  As stated, for the most part, these are mechanically and electrically interlocked contacts.  As Richard stated, if the bridging contacts cease to make connection, you can clean and polish (burnishing) but likely your fix is not as good as new. I never had much luck with longevity after polishing.

The best approach is to bite the bullet and buy new.  Technology Research (41260 Surge Guard 50 Amp Automatic transfer switch is a reliable product and includes some surge protection.  The parent company is Southwire.  There are a host of other manufacturers, all with different features.