jagabuwana, your photos show precisely the same results which I get when I take a Mora knife or industrial planer blade, wrap in plastic film, and then pour in enough lemon juice to wet the blade. When I submerge rusty hex-head cap screws in lemon juice, the result is the same. In all cases, the stench after unwrapping or removing the lid is horrendous in a ripe cheese sort of way. Everything turns black, but when I clean away the sludge from the blades, the black colour lacks staying power. If it wasn't for this last bit, I might have concluded that the sulfur could be dispensed with, and lemon juice alone might work well enough to achieve a stain of sorts. I've been informed that sulfur can be bought at home improvement/hardware/gardening supply stores. I may have to buy some and try this alchemy to see whether sulfur is indeed the crucial ingredient which gives the black the staying power to endure even toothbrush scrubbing. If not, I may have to set about establishing myself as an amateur hobbyist mineral collector to get my hands on some arsenic as found in nature.
|