Do you ever have a reload where the crimp dished in a little too much leaving a small opening in the center? This can happen when your reloader is set to crimp one kind of shell and you use another. It can also happen when loading shells that use a filler wad and you don't get the shot column high enough, easy to do loading the Short Ten.
When this happens these shells will often leak shot shot making them unusable. It's difficult to open the shells after they are loaded and fix it. There is a simple solution. Drip some candle wax in the center of the crimp and seal the shell.
Old timers used to do this to waterproof their paper hull reloads even when the crimp was right.
I have thought this was something everybody knows but then yesterday when I "fixed" a couple of old Remington SP hull 10ga reloads and thought I would share with those who might not know of this trick.
PS. Don't do this on your reloading bench, that is not a good place for an open flame