I use hydrogen peroxide. It is the best cleaning agent I have found for the pee stains. Hydrogen peroxide will bubble out any bodily fluid, and it completely gets rid of the pee.
What I do is put the H2O2 (hydrogen peroxide) in a DARK spray bottle (can't be light, because if light leaks through it breaks the H2O2 down into water), spray a bit on the areas that have been peed on, and let it sit for about five minutes. Then I take a scrubbing brush and scrub the area, let it sit a few seconds, and wipe it down with a damp wash cloth. I usually let the ledges sit out in the sun if I did a hardcore cleaning. This helps break down any excess H2O2 that was left behind.
I have used vinegar/water as well, but H2O2 works wayyy better IMO.