Deleting vars local to a function in a class

Is there any advantage to deleting vars instantiated within public or private functions in a class, or are they removed from memory after the function has been invoked/run? The function below is completely arbitrary for example:

private function someFunctionHere(_ar:Array):Void {
        var _swf:String = _ar[0];
        var _nm:String = _ar[1];
        var _num:Number = 5;
        //use them here
        delete _swf;
        delete _nm;       
        delete _num;