Unearthed my 1964 printing of the 1949 "Coin Collecting Merit Badge Series Boy Scouts of America". Page 34, "Caring for Your Coins" reads to wit : "Once you get an addition for your collection clean it. You can wash it with baking soda and water ..." Should have been "demerit badge" ; a bunch of 12 year olds gone wild on Grandpa's coins with Arm and Hammer.
Please note the date of that. Back then everyone said to clean your coins. Gas for your cars had Lead in them back then too. Was no cures for many forms of illness. You could sit on a porch without getting shot. You could walk down streets at night safely. Lots of stuff was different then.