Cleaning pet or human urine out of a memory foam mattress is not any more difficult than cleaning it out of a traditional mattress, but the process is slightly different. The first step in both processes is to soak up as much of the urine as you can with a towel, but you must be careful not to push on a traditional mattress for fear of pushing the urine more deeply into the fabric. With a memory foam mattress, you'll need to apply some pressure to force the urine out of the foam and into the towel.
Place absorbent towels over the stain and press them into the mattress to absorb as much of the liquid as you can. Press into the stain, but don't rub or scrub the stain as doing so will spread it. Use as many towels as you need to pull the moisture out of the memory foam. If the urine is already dry, skip this step and move on to deodorizing the mattress.
Combine distilled white vinegar and water in a spray bottle, using a 50/50 ratio. Lightly spray the stain on the mattress and allow the mixture to sit on the surface for 5 minutes. Blot the vinegar-and-water mixture back out of the mattress with a clean, dry towel. If the smell remains, repeat the process. If the urine stain was dry when you started, press towels into the mattress after spraying it with the deodorizer to get it as deep into the foam as you can.
To absorb residual odor from the mattress and to draw out any remaining moisture, sprinkle the stain with baking soda and allow it to sit overnight. Vacuum the baking soda off the next day and recover the mattress only if it is completely dry. If it is not, set fans in the room, arranging them so that they blow across the mattress to dry it.
Protect your mattress from future accidents or spills by purchasing a waterproof mattress cover. These covers are machine-washable and will protect your sensitive memory foam from future harm.