rat smell

Hi, I got three male rats over a month ago and they really smell. I clean out there cage once a week and do a spot clean every three days. They have paper bedding and a litter tray ( which they are trained to use, but if course they still pee in the bedding a bit.) I’m not sure why they smell so...

I’m wondering if using wax melts will help with the rat smell. I have four girls now and my boyfriend was told by someone else that they stink when we only had 2 at the time. My boyfriend has noticed it as well. We know candles aren’t safe and we aren’t allowed to use them in our apartment...