Load/unload external files

this is probably a seen issue, but i really cannot grasp what to do… by reading the other posts…
maybe someone can make my life happier today…

here is my problemo…

i have a main movie, in every 10 frames, i have an external movie being loaded. My issue is that the previous movie wont leave the screen…

here is the code i have to load the swf file in the specific frame number:

 
var imageRequest:URLRequest = new URLRequest("home.swf");
var imageLoader:Loader = new Loader();
imageLoader.load(imageRequest);
addChild(imageLoader);
imageLoader.x = 0;
imageLoader.y = 140;

how do i unload this particular movie clip when another is to take its place?

sooo appreciate any help.

thanks!
ps. dont forget im a newbie…