I'm not sure what the batteries cased were made of back in the 50s and 60s but the "myth" came from the idea that the concrete will "pull" the water/acid out of the battery. With today's plastics it's not a problem.
Bakelite may have been the old material and it may have been porous.
Scott
Bakelite may have been the old material and it may have been porous.
Scott
