It's a good thing before you leave your campground to dump and then fill it with water and dump and do it a couple of times. More so if its hot out to really get it rinsed out before you leave.
My bathroom sink dumps into the black tank. So it's real easy to just let open up both faucets run full force until the black tank fill ups and then just go outside and pull the valve to dump.
AND always put a couple of gallons of water in the tank when you leave so it can slosh around while you drive back home.
....and make sure you don't have the bathroom fan on when you flush or any fans on that you have in the other vents if you have a split bathroom!