Oxidation and bare silver or silver coated wire???

Bare wire should be fine...
it cant hurt to treat the bare conductors and binding posts with Caig pro gold...This molecularly bonds with the base metals and will prevent residue and oxidation from occurring.. or at least prolong it.
PRO Gold can be bought at audioadvisor.com
Good luck,

I'm not a metallurgist but I've heard that oxidized silver actually conducts better than new copper.

Silver can oxidize but the process is slower than copper oxidizing. But, the oxide of silver is a good conductor, unlike that of copper. However, silver has another trait: it tarnishes. There are always trace amounts of hydrogen sulfides in the ambient air from typical carpet cleaners to lighting matches. Tarnish is not a good conductor; it does build up slowly and therefore you should periodically clean the connections - same as with gold plated spades (gold is not supposed to oxidize but my connectors seem to have some build-up after a year or so) and other types. Just part of the fun... :)

If you treat them with Caig every 4 months it should not be an Issue.
Bare wire connection is best.
Spade's Bannana's just get in the way of the music.