A catheter for use in a subject's vasculature includes a rotating and axially movable instrument. The instrument includes a rounded element at its distal end connected to a body having a spiral shape. The instrument is at least partially disposed in a lumen of the catheter and is configured for axial and rotational motion within the lumen between a proximal-most position and a distal-most position, where the body includes at least one edge configured to promote removal of a target substance from the body passageway upon contact with the target substance.