with the Freon I spray it with the can upside down so it is liquid when it hits the bolt. You need to wear gloves because it will cause frostbite burns if the liquid comes into contact with your skin.
They sell a product at the auto parts store that is supposed to freeze the bolt...it didn’t work. I never even thought of just using refrigerant...I assume by ‘freon’ you mean R-134? A can of real Freon is probably worth more than the caliper.