I haven't tried it. On wood, the manufacturer recommends a chisel, a
knife, or sandpaper. On porcelain I'd try a metal scraping tool on such
as a knife or a razor blade. The glue may be easier to scrape when at
130 F or hotter, so boiling water or a hair dryer might help.
Pumice and vaseline have helped on hands. Pumice might work on porcelain.