As the 3 posts above mention, you are going to have some exposed copper somewhere which is going to oxidize. I asked Ray Kimber about bare wire connections at Audioasylum (I use 8TC) and his response was that a number of the Kimber cables were actually designed to be used with bare wire connections (the 8TC is a a little fat for that but I'm able to do it at my speakers and would do it at my amp if I could). He suggested just to tighten down the connection and not worry about it. After all, if you tighten it down and get a solid connection, it's not going to oxidize where the connection is.
Question for users of bare wire ends speaker cable
There have been discussions on the use of bare wire ends as being the best way to get a good quality speaker cable connection. The only downside is the need to re-do the connection often because of the corrosion of the copper. As a part way measure can the ends be soldered or something else, to cut down or stop the corrosion without adversely affecting the signal??