I have a couple of old, worn, and worthless Indian Head cents
that may have BD. But they've had it for as long as I can remember and it hasn't progressed any. It is not worth the trouble of treating them.
Many of my wheat cents (again, old and worn) have normal verdigris spots, and this is very common on old pennies; I see it all the time. I even see verdigris spots (not BD) on nickels often. Even on certified nickels.
BD can only be spread coin-to-coin by direct contact, so when my 1865 2 cent piece is finished with "cancer" treatment, I will be putting it back into a 2x2 cardboard holder and into my album.