What is the best way to stir the rust sealers?

Stir in an up and down fashion, NEVER IN A CIRCLE. When you stir moisture cured urethanes in a circle, it draws in moisture and drastically reduces the work time and shelf life of these products. Using a wood paint stick, use it to pick the solid content up from the bottom of the can and stir up and down to distribute the solid content throughout the body of the paint.