How can I effectively remove dry cat pee from a mattress?

To effectively remove dry cat urine from a mattress, you can try using a mixture of white vinegar and water to clean the affected area. First, blot up as much of the urine as possible with paper towels. Then, spray the vinegar solution onto the stain and let it sit for a few minutes before blotting it up with a clean cloth. Repeat this process until the odor is gone. You can also sprinkle baking soda on the area and let it sit for a few hours before vacuuming it up to help neutralize any remaining odor.