Grandfather Crumbs

The residue in a bag of weed that, because of its size, has filtered through the larger buds to the bottom, getting to about the size of a crumb that would be stuck in a grandfather's beard.

Let's roll a joint, I've got a lot of grandfather crumbs.

What the fuck? When he chopped the weed he left me with all the grandfather crumbs. What an asshole!