I have an very old double barrel m/l shotgun, it was a gift from a friend. His neighbor obtained from a relative when an old barn was torn down, the shotgun was way up in the loft. Likely not used in well over 100 years.

The night I obtained it I ran a cleaning rod down the barrels, yep, the left had a charge. Wormed out wads, shot and black powder.

Check them all folks, even that reproduction you bought from a newspaper classified ad!!!