I clean my cage once a week ( sometimes once every week and a half if I am super busy). I had my 2 girls in a large bunny cage ( just got the CN yesterday) But i found it never started to stink until I needed to clean it, it smells excellent then as soon as it smells bad , I clean it ( depending on the weather its about a week in between.) Since I have only 2 girls, it doesn't get dirty as quickly so I never found a need to clean it every few days ( cept in the summer).
I am also a firm believer in baking soda. I buy those 'Fridge' ones that have too pieces on either side oyu rip off so that the air travels through the baking soda. One of these by the cage and it is insanely fresher. I can tell when its time to change the baking soda cause it gets smelly, then I change the box and its better. ( it lasts a month) I also clean the cage by letting ti all soak in a baking soda bath ( just soda and water) pulls out all the odor that's stuck in the plastic. I swear baking soda is my best friend ( I use it as a face wash too .. but that's a story fro a different thread ; ) Bottom line, make a baking soda paste and use it as a mask. sooo nice) Also, I scrub the toys and bottom pan with Johnsons Baby shampoo. It smells like apples (ish) and is really gentle, so I don't worry about the rats.)
And when I do the laundry, I toss in maybe a half a cup of pure white vinegar with e fleece, then just use a tiny amount o detergent, and the fleece comes out really fresh, rather then the lingering rat odor.
Then every month or so, I take a baby wipe sprayed with a bit of vinegar and water and wipe down the cage bars.
All in all, the onyl time I smell the rats si when I leave the cage fro too long , or I stick my head right inside haha. Or when I give them veggie. God, I hate the smell of rats that have just eaten veggies. :sick2: