You know, I use a coffee grinder I got at a thrift store to do my peppers and spices. You have to do small amounts, but they sure do well with no mess! Just a suggestion.
Even new ones are pretty cheap. (Just don't grind coffee in them once you use them for spices!!!!)
I get an absolutely beautiful powder out of it! I do with my thai chilies. I also make my chipotle mustard by grinding my spices fresh for it. So everything from chilies, to mustard seed, to cloves go in that baby!