How can you get rid of white rabbit urine stains from a hutch?

I too store my white rabbits on my hutch in the dining room. they're sooo cute! I put a piece of my wedding china in between each bunny. I have also had problems with their urine stains. Toothpaste rubbed onto the stain helps somewhat, but I will watch your question with great anticipation for a solution to this very common problem.