═══════════════════════════════════════════════════*/ Allow say, the combination of potassium hexacyanoferrate(III) and phenolphthalein may be the rust indicator. And we use to detect the rusting of the iron nail. And The end result is: the suggestion, head location with the nail surface blue color; the straight location seems pink color. #seven S2RT If https://tropicallimos.co.uk/birthday-limo-hire/