Reader Dr. J., a pathologist and coroner’s physician, e-mails in regarding this post:

My colleagues and I don’t think placing a mixture that contains
concentrated sodium hydroxide into the environment would be very ‘eco-
friendly’. And OSHA (EPA, or whomever) would not allow you to keep
such a mixture at home; should you be the type that wants to keep your
loved one on the mantle in a container.
Actually, why not just let people be buried without any type of
container or casket? They could then give their nutrient rich body
back to the earth.

The simple pine box would be good for the environment, but I still like my idea of the catapult-into-the-volcano best.