how to clean out old powder from horn?

[adkmountainken]

a friend gave me a nice powder horn that has old, crusty, dried powder in it. I used a piece of wire and got most out. will hot, soapy water and rinse get the rest?

[rollingb]

I wouldn't use water if it was my horn,.... maybe try a few ounces of #4 lead shot and a good shaking, would knock any remaining powder loose. 

[P.W.Berkuta]

a friend gave me a nice powder horn that has old, crusty, dried powder in it. I used a piece of wire and got most out. will hot, soapy water and rinse get the rest?

I'd use sand - and shake the heck out of the horn - maybe do it a few times.