Cleaning my new horn

[ALDeer]

I recently purchased a banded horn from an on on-line auction.  It arrived a couple of days ago and I discovered that it is partially full of old powder (i think).  The powder is wet and is has set up as a hard mass.  The only recommendations that I could find on line were to dissolve it water and mild detergent.  I have tried that and was able to remove some of the material but the going is slow.  Does anyone have any experience and better way of cleaning out the horn? 

[rich pierce]

I’d get a coat hanger, unwind it, round over the end, and use that. Possibly dribble 50 BBs in there, plug, and shake vigorously.

[ALDeer]

Thanks for your quick response.  I'm trying to dry the powder now and will give your suggestion a try in a couple of days.