Those recycled, repurposed, reused bag mats are slowly coming along, I've been trying to work on mine at home some, knowing full well, if I only do it at the Crochet Club meetings I'll end up being 90 years old before I'm ever finished!
I started with white bags using single stitches. Slow progress, for sure. Switching to double-crochet when I went with the gray bags has improved my speed from creeping to slow.
I'm thinking of doing blue next, then gray again to begin making sections. Since my beginning strands seemed to "shrink" on me (probably those single stitches) I'm going to do a tan border around the whole perimeter once I get it long enough, just to make sure I have some extra width.