I have a 682 Norcold and tried removing the baffle from the top with a coat hanger. There is a return flange over the flue. You can not look down and see light at the bottom with the return flange in the way. On my friends Dometic you can. I tap on the flue with a hammer to remove loose rust and vacuum it out every year. I thing I would have to remove the refer to get at the return flange and baffle. This is my experience and will be following this thread to see if there is a trick to remove the return flange and baffle without removing the refer.