What is the most effective way to eliminate the smell of cat pee on a mattress?

To effectively eliminate the smell of cat pee on a mattress, you can try using a mixture of white vinegar and water to clean the affected area. After blotting up as much of the urine as possible, spray the vinegar solution onto the mattress and let it sit for a few hours before blotting it dry. You can also sprinkle baking soda on the mattress and let it sit for a few hours before vacuuming it up to help absorb any remaining odor.