Help with duplicateMovieClip method

1

i’ve used the following code to create instance of my movieclip “fly”;

while (i<25) {
fly.duplicateMovieClip(“fly”+i,this.getNextHighestDepth());
i++;
}

now i’im trying to remove them using actionscript
i tried with each of the code below

clearBtn.onPress=function(){
_root.fly.removeMovieClip();
}

clearBtn.onPress=function(){
_root.fly.clear();
}

clearBtn.onPress=function(){
_root.fly._visible=false;
}

but it doesn’t seem work. Does anyone Know how can i do it ?
thnks