For the budget minded, try the hospital grade plugs (orange in color) at Lowes or Home Depot. Before installation clean all the contact points, including the bare wire you are about to connect with Tea Tree Oil. (Tea Tree Oil can be purchased at any Wal-Mart for about $ 3.00) Tea Tree Oil is an excellent contact cleaner no matter how dirty your connections are, or how clean you may think they are sonically.
This is a very cost-effective upgrade.