I do not own crow bones, neither have I worked magic with anything crow related other than acknowledging certain animals sacred to certain deities. But understanding the symbolism that crows have could give you an idea of the magic that can be done with it.
Crows have long been associated with death, so I imagine these bones could be a good booster for harmful curses (and bad luck). As a symbol of creation and 'cleansing', you could use them in purification, bringing in the new and good.
Bones are a very good divination tool, in lore, crow dominates the three aspects of the day, that represent our past, present and future, this can help you fortell.