Well that's cool, perhaps it's got some kind of latex in it......I use soap and water to get latex paint off whatever I get it on if it's dry. That greased lighting stuff is really good stuff, and yes you're correct don't use it on aluminum even if it's dilluted.
by the way, greased lightning is the best tire cleaner I've ever used. I spray it on straight or maybe 60/40 and let it soak for about 30 seconds, then spray a little more on and use a light brush to clean them then powerwash them off and they look new when they dry.