How do you clear a pre-made map (such as Earth) from the pre-set leaders and civs, so that you can pick who you want each time? (Also so you can save any edits you made to the map without pre-setting civs yourself.)

I don't think you can. Unlike Civ3, Civ4 has an absolutely terrible world editor. However, somebody made and published their own Civ4 editor that may be able to do this, but it only creates and edits vanilla Civ4 maps, not Warlords or Beyond the Sword maps.

Thread moved.

moved to where?