Dennis,
Being aware of it is most of the battle. There are a couple things to try to eliminate the biceps.
First, as I show in the "release tips" video, keep that string wrist OUT, NOT in!! This simple thing will help to take the biceps out of the shot.
Second, think of your string elbow as a LOOSE HINGE. As soon as you apply biceps, the string elbow will move outside the arrow line -- every time!
If you can learn to draw by levering only the upper string arm (humerus) around your spine, the elbow being relaxed will allow the relaxed forearm to maintain arrow alignment. It is not something you do, it is something that happens.
When I do this, as I get to full draw, it FEELS as though I am leaning against a wall with the string side of my back. Now, as you go through expansion/release, you just lean on the wall harder as you relax the finger hook.
That release is done with the string shoulder moving back (scapula/shoulder) NOT the biceps.
MOVE THE BONES, not the muscles.
Sure wish we were closer easier to show and do than to "tell."
Arne