How would I remove this attachMovie?

Actionscript Code:
var fm_mc = attachMovie("my_object","my_object" + j,j);

I have tried these codes with no success

Actionscript Code:
fm_mc.unloadMovie();
unloadMovie(fm_mc);
removeMovieClip(fm_mc);
unloadMovie("fm_mc");
removeMovieClip("fm_mc");

Please help, I am using flash 10.2, in flash professional 5.5

Thank you in advance.