In the mortuary trade, crematoriums are known to be fickle and their operators inept or sometimes cheap, unwilling or unable to operate the equipment in the way which produces the fine ash survivors expect.
When my dad died (many years ago) we talked about the possibility of spreading his ashes on the Great Lakes, where he'd taken such pleasure sailing as a young man. Someone took me aside to let me know that if we did that, the odds were good we'd be doing ourselves a favor if we simply dropped the entire box into the water rather than opening it for a sprinkle. Even when the family was prepared for a person's death and welcomed it as an end to suffering, nobody wants to see identifiable bits.
We kept the ashes in the package the mortuary provided, which looked very much like a present gift-wrapped at one of the better department stores. We joked that in a pinch, we could lift the lid and use it as an extra ashtray. ("Hey, Ed seems to be gaining a little weight there!" My dad would have thought that was hilarious, too.)
When my mother died, we had her ashes and my father's mingled and interred together.
Maryn, who's given the kids explicit instructions for the cheapest casket, burned hot and fast
