Quote Originally Posted by bokuza View Post
Cedar is the big no no. Pine can be kiln dried and if you buy a decent low dust brand. Pine absorbs urine better than aspen. Aspen is the safest choice supposedly however I find that the amonia build up from unabsorbed urine causes health problems in sensitive rats. It costs more and needs to be cleaned more often.
This. I've found that with Aspen I'm changing bedding almost every other day.