I have smoked in the Harley Drum over 20 times and it still looks the same. No worries about getting dirty. I am sure the other Brothers on this site will tell you the same thing. If you go over to the UDS photo post you will see some awesome drums and they all get used.
Dave- I did a couple with high heat paint put I could not get all the colors I needed. So I contacted several paint manufacturers and I was told the same thing. Most paints will not start to burn off until 450 F. I have found this to be true, since I don't smoke over 350 max I have and also all the people I have made UDS for have never yet had the paint fade or burn off. So I use Krylon Exterior spay paint without any problems.
My Harley barrel has Had many many 12 to 14 hour cooks and still looks new.