Blot up as much urine as possible with paper towels or clean cloths
Strip all bedding and wash it separately in hot water if the fabric allows
Mix equal parts white vinegar and water
Lightly saturate the stained area with the vinegar solution
Blot the area again with clean towels
Sprinkle a thick layer of baking soda over the damp area
Let the baking soda sit until the mattress is completely dry
Vacuum up the dried baking soda
Apply an enzymatic pet urine cleaner to the affected area if odor remains
Let the cleaner sit for the time listed on the label
Blot and air-dry the mattress fully
Use a fan or open windows to speed drying
Repeat the treatment if the smell persists
Avoid using bleach or ammonia
Use a waterproof mattress protector after cleaning