Well let's think about bones then. If you were to use bones in casting a spell, it is more focused. If you bring something in you shoe something out. The less you have the more open ended the spell is, but with a recipient, in a blessing, you would need to have things that remind you of them, or, focus on them more, bringin them into the spell. Thinking about someone and having thier picture are two different things, but doing both focuses more, yes?
Now with bones, what does that bring into your spell? Is it death magic? Is it strength of what remains? What do the cosmos think of that? Do you think you cast your own spells? Nonsense! It is always the fairies that cast them for you.
So what does a ferie think of bones, what does it mean to them? Basically it should mean the remains of an animal. The sangomas of South Africa use chicken bones to tell the future, so, using something that is old and gaining thier insight into it would probably be the best thing to do, or think about. Seeking wisdom in a matter. Do not burn them, do not lick them, but rather lay it up to chance - maybe placing the bones inside a ash cicle with you will lend you some wisdom?
!! Another smoooooooth one with the mirror ball !!