There are hundreds of variations of Civil War projectiles. They were filled with a black powder bursting charge, which will explode just as well as the day it was fired, if the black powder is dry. There were a few designs of impact fuzes which would explode the projectile if the fuze received an impact, therefore without identifying the fuze first, it is very dangerous to agitate or hit projectiles.
A number of bad things happen when people recover UXO projectiles. They try to drill them out to wash out the black powder, and sometimes detonate the powder with the heat of the drill. Other dangers exist when people think the projectiles are solid steel, and they place them by their fireplace as antiques. When the cold Winter night arrives, they build a big fire and all gather around the fireplace, and the projectile overheated by the fire detonates and kills the whole family.
For those members that appreciate land mines, civil war cannon balls were buried as landmines, by retreating troops. They removed the cannon fuze and replaced it with the friction fuse used to fire the cannons and attached trip wires to the friction fuzes. In one instance, the retreating troops were captured and forced to dig their land mines back up.