Jolly-John, I would recommend you do the barkeeper's friend by hand. It's pretty abrasive and can remove the gloss from a porcelain sign if you're too aggressive. Dilute it down to a runny paste consistency with water and gently rub by hand until you get the results you want. Rinse it off occasionally and wipe dry to make sure you're not cutting into the gloss.
Re: CLEANING PORCELAIN SIGNS
[Re: Mike M.]
#706360 Fri Mar 16 201810:22 AMFri Mar 16 201810:22 AM