Preface: I don't want enough information that this needs to go into the Research subforum. In general, is there a value in having relatively inert material mixed into an APCP propellant? Obviously, titanium flakes/powder give you a sparky motor, at the cost of a lower specific impulse. Would you have the same reduced impulse with no sparks if you used a more inert material like silica? Is the reduction in performance roughly linear with percentage of inert material (20% inert material has 80% of thrust/impulse of standard)? Long ago, I had a notion of a service where one would receive people's/pet's cremated ashes, mix them into propellant, and launch them on a final flight. In theory at the right price point, you might be mixing so much that the limiting factor would be how many rockets you could launch since someone else was basically paying for the fuel. I shelved it as impractical pretty quickly, especially since I'm not really all that keen on research motors. After bringing it up again in the R rocket thread, I got to thinking about it again. Cremated ashes are largely calcium carbonate (aka limestone), so they might have enough oxygen bound in to be useful in propellant. Again, please keep this qualitative so we don't end up in the Research forum. And this is absolutely a crazy notion and likely not commercially feasible, though it may be a good way to send off a long time motor mixer.