Canadian Jewellers Association · Toronto : Maclean-Hunter Pub. Co · leaf 124
value : Prepare a bath composed of nine parts of rainwater and one part of sulphuric acid. Place the coins in thisbaih for the time required to dissolve the sulphide which hasblackened them. Five to ten minutes are usually sufficient.After removing them, plunge them into clear water ; next washthem… … This column is opened fop the purpose ofgrlving short and concise answers to enquir-ies pegapding wratch pepaips, op anything elseconnected \vlth the Jewelpy business. Thecpaft apo copdially invited to dpaw on thekno-wledge of oup expepts ■whenever theythink that w^e can be of any assistance…
Jewelry · Jewelry trade
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