How do I uninstantiate an object?

Question

I have a slideshow that runs from the moment it's instantiated.  When I stop it I remove from stage and set to null.  I thought that setting it to null would remove it from memory but I was wrong it keeps outputting trace output until I close the swf.
import com.droolpigs.*;
var slideshow:Slideshow;
start_btn.addEventListener(MouseEvent.CLICK, startIt);
stop_btn.addEventListener(MouseEvent.CLICK, stopIt);
function startIt(e:MouseEvent):void {
    slideshow = new Slideshow();
    addChild(slideshow);
function stopIt(e:MouseEvent):void {
    removeChild(slideshow);
    slideshow=null;
// it's removed from stage but keeps runnung

Answer 1

to properly remove the slideshow  class properly, it is not enough to null it, you also need to null any other references to it as well event listeners, I normally kill as well arrays, vectors, so you clearly clear the memory needed. to be honest I never managed to properly kill instances of a class by only using System.gc(). While looking at the profiler haven't seen any difference.