Garment makers used pinking shears to cut out their pattern pieces in order to minimze unraveling since all the edges are not cut on the straight grains of the fabric (think A-line skirt). Instead of whacking them as Gale suggested, take the jelly roll outside and unroll it and gently shake the strips. Don't brush the edges while it is still rolled up, as this will loosen the small pieces of thread. They will come out of the pinked cuts and you will lose that fabric, throwing your measurements off.