From time to time we have people contacting us saying that they have a problem with their china tableware.
The issue is grey, silver looking “scratch” marks or lines that appear on the surface, mainly of the plates. The customer’s natural instinct is that there is a fault with the glaze of the plates.
The glaze used on the tableware is fired at very high temperatures and is extremely hard – harder than most of the metals that are used to make cutlery. Some of the metals used in the manufacture of cutlery are quite soft with highly stainless steel being particularly soft. The hard glaze on the china abrades the metal of the cutlery leaving a deposit of the metal on the surface of the glaze, which appears as a characteristic pencil-mark.
These on glaze marks can normally be ‘polished out’ by the use of a mild abrasive polish such as ‘Bar Keepers Friend’ or a sliver polish remover and a soft cloth.
Occasionally, the use of cutlery can produce small surface scratches in the glaze. This is caused when excess pressure is exerted onto the glaze through a small point of contact such as when a sharp knife blade is pressed down onto a plate. The excess pressure produces small cracks in the glaze and when the knife blade is drawn across the plate, metal from the knife is abraded and deposited in the crack beneath the surface of the glaze. Unfortunately no amount of cleaning will remove these marks as the metal is embedded in the cracks.
So if your tableware has evidence of these grey marks, do try to clean first as suggested.
Only seek further advice should the marks not be removable. At this stage a test sample might be returned to the factory for analysis to establish the likely cause, which can include faulty manufacture.