Thanks for all the great ideas guys. WD-40 .... Comet Fever, thanks for jarring my memory ... I probably would have gotten to that sooner or later. This stuff does have the vibe of being more adhesive than anything, and that stuff is great for removing old decals and glues, etc. Whenever cleaning something where preservation is a goal, I try going for the mildest approach first. I'm going to hose this thing down in WD-40 and let it sit in the sun a bit.
+1 for the WD40..... It's amazing what that will get off without hurting anything..... I use it to clean windshield sealer off the window frame, removes the goo and doesn't hurt the paint.....