It is shell covered by lucite. The lucite can melt when worked and this happened here.
I've been doing much more office chair shining with my seat lately. This physical work has taken a distant back seat to that so I have fewer opportunities to get dirty. That and a fingernail brush for washing up. My chore to do list is lengthening so something will have to give.
I received the club September newsletter, via email, today. CJ has a terrific tale to tell. I am sending good thoughts to Chuck and hope he holds up.