Tinting out an object

I’ve done a lot of research and I can’t find exactly what I need. I need a way to dim out a MovieClip. First I tried adding a simple Bitmap with some alpha transparency, but because the MovieClip isn’t perfectly square that doesn’t work right. I then tried the colorTransform class, but that removes all the detail from the object, I just need to make it a little darker, anyone got any ideas?