Abstract: A currency handling system comprising a fitness detector. The fitness detector comprising a thickness detector, a limpness detector, a soil detector or a combination thereof. The thickness detector comprising an upper roller displaceable in a predetermined arc by a note passing between the upper roller and a lower roller. The limpness detector comprising a single driven crackle roller comprising an elongated central bulge and two outer bulges, wherein the central bulge is in conforming relation to a flexible belt. Sheet metal guides further facilitate note deformation and sound production.