Beech-nut hulls sounds like an interesting candidate. Thanks.
I have another winner! Seven years ago, I harvested whole branches of rosemary, enclosed them in Agribon AG-15, and hung them on the back porch to dry in the sun. I ignored it. There it was, hanging today, high above one of my seedling trays.
All the leaves were completely brown, but highly aromatic if broken. The relatively thin and kinked stems are a solid wood, requiring a cutter to "break" a 1/4" diameter.
I burn tested the stem first. Very impressive. It's distinctly aromatic, but does not smell like the culinary herb, rosemary. Those old, dried, brown, seven-year-old leaves, on the other hand, smell like I'm roasting rosemary chicken--not suitable.
So dried rosemary stems go on the "nice for Latakia" list. The leaves do not. I'm wondering if the same may be true of other mint family herbs. That is, the herb isn't right, but its dried stems may be perfect.
Thanks to GreenDragon's inspiration regarding grandma soap, I think we are approaching a generalizable rule of thumb. I'll have to try just the stems of more herbs. These (or their close relatives) may be the "herbs" used in the legendary Latakia process stories.
If you grow mint family herbs, save the stems!
Bob