Blot up as much urine as possible with paper towels or a clean cloth
Strip all bedding and wash it separately
Mix equal parts white vinegar and water in a spray bottle
Lightly spray the stained area without soaking the mattress
Blot again with clean towels
Sprinkle baking soda over the area
Let it sit until completely dry
Vacuum up the baking soda
Apply an enzymatic pet urine cleaner to the spot
Follow the product instructions exactly
Let the mattress air-dry fully
Use a fan or open windows to speed drying
Repeat the cleaning process if the odor remains
Place a waterproof mattress protector on the mattress after it is dry