Batting strips are perfect for using for scrap piecing placemats. I did a tutorial under Scarp Busting on taking your batting strips and sew and flip scrap fabric down the length. Once you have a section done, trim it straight and sew several of these sections together with 1 inch sashing. Cut to placemat size, put a backing on and straight stich down the sashing strips and bind.
As for you 12 inch practice squares, I might sash them QAYG style and make a picnic or car blanket from them.