Sensitive content is securely shared. In addition to the foregoing, other method aspects are described in the claims, drawings, and text forming a part of the present disclosure. This treatment chemically reduces the hygroscopic sulfitessulfates left on the surface after the main etch step. Accordingly, even in the case where a common inexpensive electromagnetic valve is used, it is possible to accomplish a smooth feed motion. In certain embodiments of the invention, a signal coding circuitry maintains an improved perceptual quality in a coded signal having a substantially music-like component.