How to unload swf

programming flash
1

i’m using the code bellow to load a swf


function carrega():void {

	var mcExt:MovieClip;

	
	var ldr:Loader = new Loader();
	
	ldr.contentLoaderInfo.addEventListener(Event.COMPLETE, swfLoaded);
	ldr.contentLoaderInfo.addEventListener(Event.INIT,carregando);
	
	ldr.load(new URLRequest(nomeArquivo+".swf"));
	ldr.unload();
	function swfLoaded(e:Event):void {
		TweenLite.to(container_mc.window_mc.carregando,1,{alpha:0});
		var mcExt:MovieClip = ldr.content as MovieClip;
		ldr.contentLoaderInfo.removeEventListener(Event.COMPLETE, swfLoaded);
		
		container_mc.window_mc.textos_mc.addChild(mcExt);
		mcExt.play();

}

the problem is that I can’t unload it. How do I do it?