Remove color?

[Pattt]

If I’ve set a color for an MC with new Color(),
how can I remove that color again?

onClipEvent (enterFrame) {
 if (this.hitTest(_root._xmouse, _root._ymouse, true)) {
  c = new Color(this);
  c.setRGB(0);
 } else {
  // remove color
 }
}