Normally some continuous & quick pump restarts should do the job. Just don't let the liquid to calm down after each "push" and ofcourse, leave a port open so that the air can get out.
tilled my PC back with a book and leave the cap off. Some of the soap bubbles did come back ( I used a drop in the loop for unyielding fittings and a guide said to add for water tension ) . Now after 2 hours the bubbles are gone and 1 C idle drop. I'd let it run a evening with the cap off.