Black stain spreading on keris during vinegar cleaning

[jagabuwana]

Originally Posted by milandro

reviving this question

Rice water should work, in itself, not because it has starch (which certainly has) but because it contains Arsenic.

but i see other people in this thread have commented on the low amount of arsenic in rice.

There's trace amounts of arsenic in all kinds of foods, though rice has a higher amount (within the confines of safe).

Maybe the combination of sulfur and some arsenic is what does it, with sulfur acting like a kind of multiplier which allows for even small concentrations of arsenic to be effective. But this is a wild guess.

If I have some time I'd be interested to try adding some sulfur in with some ineffective realgar I bought off the internet and see if it yields a better result compared to just realgar alone, using the brush stain method.