Getting rid of a duplicated movie clip

programming flash
1

I use this code on frame 1:

 topEdge = 0
leftEdge = 0
rightEdge = 550;  //length of stage, CHANGE THIS 
bottomEdge = 400;  //width of stage, CHANGE THIS 
for (i=0;i<50;i++) { 
	  _root.snow_mc.duplicateMovieClip("flake"+i, i); 
   _root["flake"+i]._x = Math.random()*(rightEdge-20) + 10; 
   _root["flake"+i]._y = Math.random()*(bottomEdge) + 10; 
   
   _root["flake"+i]._alpha = Math.random()*80+20; 
   i++; 
}

and it works great, but the flakes get duplicated even when i go to frame 2. What I would like is code to get rid of the movie clip, can anyone help?

Thank you.