There are many different options when it comes to the bedding you use in your rat's cage. There's fabric, paper, wood, and even soil in bioactive cages. It can be a struggle to find bedding that helps with odor but isn't messy. For me, I personally use fleece with towels underneath which I toss in the laundry. I do this every week and spot clean and/or replace fleece every day. It's not perfect and get's smelly super quick.
I was recently approached by ZYMOX® to take a look at their new product the Cage Diaper®. I know, silly name, but it is actually quite a great product!