I reserve the PB Blaster use for the severely frozen pawl. Once in a while you need to dismantle the shifter and get a dental pick on one of the pawls to work it free. If that doesn't work right away, a drop of penetrating oil helps. I don't know if penetrating oil is as good a cleaner as WD-40, which I hear is largely kerosene. And flushing out a shifter is the only place on a bike I use it.