I have owned this 22.5 WSM for about a year now and recently the past few times I've used it, I have what looks to be rust on the inside. I keep it covered with the provided cover I always make sure it is dry when I put it away. It is always dry when I get it out and in always remove this brown/orange dust that always seems to build up in it now. Does anybody know what this is and why it keeps happening? Has any other WSM owners had this issue? Pics below...