Just finished browning a LR w/ LMF and for unknown reasons {anyways to me}, a shiny "crust" formed on some lock parts and areas of the bbl after the third coat. Carding w/ denim couldn't break through the crust, so used green Scotchbrite and that did. After removing the crust, I lightly went over all surfaces of all the parts and after 2 more coats, achieved a nicely colored, lightly etched matte finish. The browning was done in a makeshift "sweatbox" which previously worked fine. Seeing I've had after rust problems using baking soda, I've been using household ammonia and it really "kills" the rusting process. Diluting the LMF sounds like good advice and will do on the next LR. Thanks for the info......Fred