Note, the clean stuff = eaten or consumed in some way or other.Compost it instead. Better for the soil microbes than ash.
I burn because if you put "dirty" plant material into the soil, chances are whatever infected it will mess with next year's crop.
Soil health and nutrition are key to plant life.
Just like with us, or animals, put us into a "toxic" environment and not all can deal, handle, much less thrive.
That said, my worms eat ANYTHING!