I made an osage bow that I wanted to quicken the aging on. I put the bow on a couple of blocks of wood off the floor. Then put ammonia in glass jars (3) and positioned them evenly next to the bow. I draped some plastic sheeting over it all and tried to seal the edges down to the cement floor. I left it for a couple of weeks. It worked pretty well. It still had a little bit of "osage color". But definitely darkened a bit.