I recently purchased a Mirage Omnisat v2 center channel which I connected using Straightwire speaker cable with banana plug terminators. The binding post of this speaker will accept banana plugs of course, but the mechanism is spring loaded and I was never comfortable that I was getting a solid connection. On the other hand the spring loaded post appeared that it would make a nice strong connection using bare wire. When I cut the bananas off and stripped the wire, it seemed to have a dark grayish color on the outer strands and not a smooth feel. I tried cleaning the ends with a paper towel and then with some Radio Shack contact cleaner I had in the garage. It cleaned somewhat, but not completely. the inner strands are the color I would have expected, but am concerned that whatever is on the outer strands is compromise the contact with the speaker terminal. Would that be correct? And if so, is there a product you can recommend to clean the ends so I can be sure I get the best electrical contact?