I have a rabbit and two guinea pigs, and there are always white urine stains on the bottom of the hutch (made of plastic) and up the sides (wood). However often I clean them out, there always seems to be stains, because they pee in the same place and it soaks through the sawdust and the newspaper (plus the bunny rips up the paper, often leaving that part bare). Anyway, as a result I always have these white pee stains. I have tried scrubbing it with soap and water, and then I generally disinfect it and then put the paper and sawdust back over the top. Its not smelly, but its not very nice to look at when it is uncovered. So I was wondering if anyone has any tips? One friend suggested trying to use bicarbonate of soda?