My family has been using Quick N Brite for years and it always works well, plus it's all natural.
With the paste: you just put some in a spray bottle with water and heat, then shake it to mix it well, with liquid: just put in spray bottle. Spray it onto area where the pee is and let it soak in, after a bit scrub real good and then we usually spray febreze on it. We even use Quick N Brite to wash the carpets instead of carpet shampoo.
My family has been using it for a long time and it always works great, but we call it "The Pink Stuff" in my house :P
I hope this helps!
Amazon.com: Quick N Brite Biodegradable/Co: Home...