The Best thing you can do whith those BH's is melt them down an use them for Fishing weights.
I spend all last winder trying to make them sharp, it dosent work, the metal just wont make a nice sharp edge. There a Basis desgin and Material , just like the Bows, Great fun, but not a Killer. I got a lots of pictures on the subject, but im in the office at the momnet, so may be later i can post a few, i shot a goos with them and its worked nice, and a pig, but nothing more, good for smaller game but i would not recommend on bigger stuff.
I allso have lots of pictures of when i hit stones and stuff, they are not strong, ill try and get you a few of them late as well, and also tere expencive, you can but a allmost any other head for the same price,
hers a picture from the summer
Good luck and have fun,