Think Kitty Litter. My sister and I still aren’t 100% sure that we buried Dad under the tree and kept the Fresh-Step in the car to help out in icy weather, or vice versa . . .
With both of my grandparents, it was mostly fine grey ash, with some… well, grit and bits in the bottom of the box! The bits were like little rocks, about the size of a Grape Nut.
Eve, please pimp this book on the SDMB when you’re done, we can’t wait to read it!
Grit and kitty litter. Great descriptions as well.
Thank you all! I’m just about done with the story, and will be submitting it to an anthology in the next few days. You’ve all helped me a lot. 
Sheri
As an aside, you might want to look into the case of a well-known crematorium in the SF Bay Area. I am not sure I have the name correct, so I won’t give it here to avoid casting aspersions on the wrong outfit.
Supposedly, after cremation, they’d (say they’d) dispose of your loved one’s ashes either via air drop or dispersal at sea for an extra fee. Someone researched it and found you’d need a permit for the latter, and that the former just wasn’t legal. Turns out they just charged people and dumped the ashes on rural property owned by a proprietor of the company. They’d been in business a very long time, and cremated many thousands of people. No telling how many people’s ashes were dumped out in the weeds.
If anyone can name the correct company, I’d appreciate it. The one I thought it was is still listed on the net as apparently legit.