THAT WOULD BE A PRODUCT CALLED C.L.R. (CALCIUM LIME RUST) OR SIMILAR AND YES IT DOES DULL THE PORCELAIN TAKING AWAY THE SHINE.
USED IT ON A 1932 3' X5' PORC COKE SIGN THAT WAS ALL OVER RUSTY AND HAD ACID RAIN MARKS ON IT AS WELL. I FIGURED WHAT DIFFERENCE WOULD IT MAKE ANYWAY. I EVENTUALLY COATED THE SIGN WITH A CLEAR MARINE POLY. I DIDN'T CARE, THE SIGN WAS A LEFT OVER IN AN AUCTION AND THE DEALER WAS PRACTICALLY GIVING IT AWAY SOME 20 YEARS AGO FOR $50! GOTTA LOVE IT!

~DOC.TAG.W


DOC @ THE AMERICAN GARAGE