Back in the 1970s 'TT' drew attention to the health hazards arising from the solvents commonly used in electronic workshops ('Watch those cleaning solvents', 'TT'. August 1974, p527, and in several editions of the out-of-print Amateur Radio Techniques). This recalled how, as a new-comerto amateur radio in the 1930s, I had purchased from the chemist a small bottle of carbon tetrachloride and then often used this solvent liberally to clean my 7MHz crystal when this became sluggish in its open holder and later for cleaning switch contacts etc.
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