Last year, I picked up some used shell Leeds and the finish was flaking. Took some acetone to strip the finish off. Bick 4 and some VSC...I’m happy with how it came out.I’ve had good success using alcohol to remove finishing on a pair of black shell Alden boots, similar to what I just saw @audog post the other day on the Alden thread.
Honestly, I’m not familiar enough with what AE does to their shells (especially when there is burnishing involved) to fully recommend it, but at least I hope my suggestion gives you an idea of what shell can handle. I followed it with some good old Bick’in and Brushin’ and they came out even, smooth, and just a bit duller overall.