There is a futon in the bunny room, and one time jack got up there an peed. Never has done that before, we were lucky to have a water-resistent cover and it never soaked through the mattress, but I used the vinegar and water mix, and then I used Nature’s Miracle. That seemed to help and you do have to leave it on for 24 hours, but I also was lucky to have only the cover and so I could also pop that in the wash to finish it off. It was like new. So maybe once you clean this, you can get a water-resistent cover or a water-resistent lining that you can put underneath the cover.
I am not sure how to get it out of a mattress. Somewhere I heard borax and Hydrogen Peroxide.
Okay, so I just did a quicky google search about how to clean up pet urine stains from a mattress and here is some info:
http://www.wikihow.com/Remove-Urine-Stains-from-Mattress
http://www.associatedcontent.com/article/425203/how_to_get_rid_of_a_urine_stain_on.html
http://tipnut.com/how-to-clean-bedwetting-stains-from-mattresses/
Let us know when you find something that works.