mr. Less wrote:My ru kiln stuff is white and can confirm it does go a rather unattractive yellow. Thinking of getting some green stuff.
is there no way of avoiding this, or is this something that happens with every white ru kiln?
i have some small light green celadon cups, and because i didnt rinse them with water after usage, some of the cups now have a nasty yellow ring at the bottom
i can not seem to get it cleaned
you may try this:
> after rinsing with boiling water, rub the stained surface while hot with a piece of cotton (the type that is used for makeup removal, pure cotton, not the ones that are sold some lotion already on them)
> if it it not enough, use calcium carbonate. you put a bit of powder in the cup, add hot water and rub gently with coton. then rinse. calcium carbonate is non-abrasive on the glaze, odorless, has no chemical action and does not stay in the veins. very efficient on all glazes.
Do not use sodium bicarbonate, which is too abrasive --although you may fill the vessel with water+ sodium bicarbonate and let it sit for a few hours, but I am not sure the vein patina would be unaffected.
>Kaolin in superfine powder form could be ok too, you can use it dry or add just a bit of water (but with celadon I would use it dry then rinse).
> salt dissolved in warm water cleans a lot of things and goes away with rinsing, maybe that would work. not sure about the vein patina though.
> citric acid is natural, very effective on stains and calcium deposits, but I think it would also be way too effective on the vein patina.
even with a very soft method it is possible that fresh patina can faint a little, but it will rebuild quickly. The "old", well impregnated patina would be ok.
calcium carbonate (or kaolin) should not be used on unglazed and porous wares, of course.