Well,in my current strate i would say you need to crush them....at the very least.Solid will do nothing at all.You'll need to crush them to a very fine powder and mix with fuel.Your going to have to measure results from normal fuel and then fuel with your crushed additive to have any tangable results though.
Please....i really will have to weigh up my actual thoughts on this tomorrow...i am sorry but i'm 37 years old ...i've consumed...well too much alcohol tonight and my head is a bit...well fuzzy....but do not be frightened..just be careful.