Matress Cleaning

To get rid of the smell, completely wet the mattress top with Nature's Miracle (available in pet stores.) Then allow to dry - you may need to either flip the mattress or have him sleep in another bed to give it time to dry, because you really have to drench it.

I didn't really notice a stain - not sure if the NM got rid of it, or if we have just been lucky. But Oxyclean is great at all biological-type stains, maybe you could try spraying that on (after the NM treatment is dry.)

I don't know how to clean a mattress like that, but sounds like you've gotten some good ideas. Just wanted to mention that to avoid the problem in the future, Kohl's and I'm sure other places too have a great waterproof mattress cover. It's not plasicy, it breathes well, looks and feels pretty much like a normal mattress pad, but it is waterproof. That has saved us SOOO many times between my 3 year old's accidents, dog messes, drink spills, my water breaking in my bed when pregnant....we use that kind of mattress pad on ALL the beds in our house. Best wishes to you with what sounds like a not so fun task at all, though we all do unfortunately have not so fun cleaning projects like that come up periodically. :)

Borax! Removes the ammonia smell from urine and works great!

Sprinkle a good amount of baking soda over it (this works for pretty much all liquids, btw) let dry for the rest of the day and vacuum up before bedtime. If its not dry at bedtime you can put a towel over it overnight so that you can put on sheets and he can sleep and let it dry a bit more tomorrow. This generally gets rid of odor and stain (and we've done this a lot, my daughter just can't seem to make it through the night).

In my kitchen I use a mild bleach water concentrate in a squirt bottle instead of store bought kitchen cleaner. Our cat got locked in our extra bedroom, we think for 2 days...I know, sad we did not notice...and peed on the bed. I used the bleach water and it worked great! I just sprayed it on the bed and let it dry.