I have never had any luck trying to bring the shine back to a "cobalt Blue" porcelain sign. I've tried everything mentioned on this post so far. If one of them ends up working, please report which one, and the step by step, on how you got it to work. Thanks, Don


Don "oltoydoc" Sherwood
oltoydoc@vintagegas.com
(310)415-9562 Cel.
Vintage Gas