Just curious but do you have a galvanized wire cage? These trap odors very well. Do you have any wooden toys? If so that is where the smell is hiding. You can never rid wooden toys of urine smell, it soaks it right up. If you clean their cage once a week it should NOT smell. Your ratties should have some types of bedding to dig through or a safe plant in which to dig. You can use Rubbermaid containers and cut a hole on top,, fill it with bedding and they can dig throught that without kicking bedding everywhere. I reccomend Careresh.

Also if you are going to bath your rats you must only use a kitten or human baby formula as others are way too irritating to a rats skin. Another good brand is Aveno.

Also if you are using towls these must be changed EVERY day or the cage will become stinky very soon. It also traps ammonia which can lead to serious upper respiratory distress. A good odor neutralizer is Nature Miracle. It works wonders. Also as far as wire is concerned, it has now been learnt that wire does not cause bumblefoot and this is actually genetics that cause this painful blistering of the foot pads. But their feet can get soar but them walking on wire as long as they have some solid ground is fine.

Petsbestern:
NO RATS ARE NOT SUPPOSED TO SMELL BAD! And take this from a rat owner who lives with 20 plus of these cute critters! Why do you dislike rats? They DO NOT smell if properly taken care of. My rats are bathed twice a month and don't even need it as they are fastidous groomers. The only reason why I do this is because I show my rats. If a rat is smelly there is a problem with the cage not being cleaned often enough or a bad bedding that traps odors. As far as tanks they smell because they barely allow any air circulation which is why tanks are not meant for permanent housing.