You could use scraps of denim for a meditation pillow, and fill it with beans or rice. To sit on I mean.
Or give it away if you don't meditate. Or just use it to sit on.
I imagine the yoga pants are very soft by now. You could cut them into yarn and knit a rag from it, to put in the bathroom or by your bed. So your feet touch the soft rag.
Nice idea to reuse it all! Good luck