How can I safely bleach polyester shirts to remove stains and discoloration?

To safely bleach polyester shirts, dilute bleach with water according to the instructions on the bleach bottle. Test a small, inconspicuous area of the shirt first to ensure it doesn't damage the fabric. Apply the diluted bleach to the stained or discolored areas and let it sit for a few minutes before rinsing thoroughly with water. Wash the shirt as usual after bleaching.