bitmapData clear pixels or set alpha

What I have setup right now is one movieClip that is being used to be drawn into a BitmapData object.

That bitmapData object is being drawn on the enterFrame and I am needing to clear it so it doesnt have the previous enterFrames information still stored in it, then once it is clear draw the current information.

Is there a simple way to clear or erase all the pixel information in the BitmapData object?

If there is a way to set the alpha of the pixels I would really like to know how that is done as well. However, I want to change the alpha level of the entire BitmapData object, not just a few pixels.

Any help would be much appreciated :slight_smile: