Start by removing the wires or cables, disconnecting first the negative battery one and hooking up last so that you don't accidentally short out your battery with the same tool you are now using to loosen those cable clamps. Also, remember to remove the negative cable from the battery before only changing the positive terminal cable. Unplug the old cables from the battery, then trace them back to their other ends and unplug them there. Before you take any of them apart though, make note of how they run so that when you put them back together in a proper manner. If there is any reason at all why these wires should be replaced, carry some along for purposes of comparison while buying new ones. Replace those wires with exact duplicates! To get rid of rust and corrosion on solenoid threads or ground wire connection apply a small quantity of petroleum jelly or a corrosion inhibitor for battery terminals using a wire brush . After attaching the cord tightly with nut/bolt on solenoid/ground cable liberally coat it in grease using petroleum jelly. Ensure no strain is required for it to reach its goal point on topmost part of cell where voltage is connected prior to joining another such new power line here too. First connect positive cable to positive terminal and next join earth wire to negative terminal.