There are many sorts of bedding quite good for use on your rat. First off, do NOT use pine or cedar bedding. It has a harmful oil in it that can cuase rats to sneeze. If they sneeze, they can get mycoplasma pneumonia and that is one thing you definitely don't want to happen. So stay away from pine and cedar, although if you had to choose between the two, pine would be a bit better. BUT DON'T GET PINE EITHER!
Now, some of the good kinds are aspen and CareFresh. CareFresh is just about the absolute best (although there's another kind out their that some people really like, but I forgot the name of it). Aspen is wood shavings, but it doesn't contain the harmful chemical that pine and cedar have. CareFresh has better absorbency and scent control than aspen, so therefore it's better. Aspen is cheaper, and if you have trouble supporting your rats financially, it'll do.
Also, it is good to use a flea and tick spray on the bedding right after every cage cleaning. Many mites are known to live in wood shavings, and the spray usually takes care of them.
Depending on how many rats you have, the cages will need to be cleaned at different rates. If you have one or two rats, once a week should be fine. If you have them in an aquarium, it will need to be cleaned more often. Remember that rats have to live in what they smell, so have a heart and spend some time helping them out. They could become very sick if the ammonia builds up, so don't let it happen!
While cleaning your rat's cage, it's good to use a bleach mix, usually 1:10 parts bleach.
Remember to PLEASE take good care of the cage. If you don't your rat could get mycoplasma pneumonia. Though Lily didn't get it due to poor maintainence, myco was the disease that took her. Please, keep the cage clean. You wouldn't want to have to leave in your filth.
