The Confederate Air Force used to do simulated nuke detonations as part of their B-29 (FiFi) airshow routine. Not sure whether it involved the aceteline/garbage bag method that you mention, but I do remember it pretty well from an airshow in the early 80s when they were still cooking them off. Big flash, heat and concussion with a neat looking mushroom cloud.
I think they stopped that in the mid-80s when they triggered a diplomatic incident by setting one off at an airshow attended by a fairly high ranking delegation of Japanese military and civilian officials.
“Japanese military and civilian officials.”
I hate it for them. Bataan Death March, ya’ll.