Taping, using silicone, etc may keep the plug clean....but what about the O2 itself?? It's still being 'dirtied' by the exhaust gases without any chance of burning off the residuals. Keep mind that O2's operate at very high temperatures and tend to burn themselves clean, now that they're not heating up, I would imagine they'd have a difficult time performing as intended if plugged back up after several thousand miles of inactivity. I always pull the O2's and replace them with a plug. This thread will give you several options on plugs.

http://www.fastlouis.com/forums/view...hp?f=5&t=72759