To clean urine from a mattress effectively, follow these steps:

1. Remove Bedding: Strip off all sheets, blankets, and mattress covers and wash them immediately. Adding a cup of white vinegar to the wash helps eliminate stains and odors.
2. Blot the Urine: Using gloves, gently blot the urine spot on the mattress with clean, dry towels or paper towels to soak up as much liquid as possible. Avoid rubbing or scrubbing as this pushes urine deeper into the mattress.
3. Clean the Stain: Prepare a cleaning solution with equal parts distilled white vinegar and water, adding a small amount of laundry detergent. Spray it generously on the urine-stained area and let it sit for 10 to 15 minutes.
4. Blot Again: After letting the solution sit, blot the area again with clean towels to absorb moisture.
5. Apply Baking Soda: Sprinkle a thick layer of baking soda over the cleaned area to absorb moisture and odors. Let the baking soda sit for at least 8 hours or overnight.
6. Vacuum: Vacuum off the baking soda completely. Inspect the mattress, and if odors or stains persist, repeat the cleaning process.

For dried urine stains, a mixture of hydrogen peroxide (3%), baking soda, and dishwashing detergent can be sprayed on the stain and left for several hours before vacuuming. Avoid using hydrogen peroxide on colored or foam mattresses to prevent damage; vinegar is a safer alternative. Avoid using bleach or harsh chemicals as they can damage the mattress and are harmful to health. These methods have proven effective for removing both fresh and dried urine stains and odors from mattresses.