How do you clean pee out of a futon mattress?

Here is how you can clean pee out of a futon mattress:

1. Start by blotting up as much liquid as possible with a towel or paper towel.
2. Sprinkle baking soda over the area and let it sit for several hours to absorb any remaining moisture and odors.
3. Vacuum up the baking soda, then use water and vinegar to clean the spot.
4. Blot the area dry with a clean towel and let it air dry completely.