I know I'd read that the top vent on my Kettle could get very cruddy and stiff from use, but didn't know it could happen so quickly. After two, maybe three smokes the vent was really difficult to rotate. To the point I wondered if the rotating could damage the Kettle lid finish. I'd considered trying to clean it with soap and water in place but followed others' suggestions,drilled out the rivet and fitted a stainless 1/4-20 hex head bolt, stainless lock washer and trimmed fender washer held in pace with a stainless thumbscrew. I also lightly smoothed the edges ot the holes and outer rim. Didn't think about trying the hanger hook though, and may have to trim the bolt shorter.
It was interesting to me to see the buildup, shown below.
Thanks folks for the shared knowledge here. It helps immensely.
Don