Thanks, David2000, for the suggestion. Since posting I found this, from five years ago:
https://the75andztclub.co.uk/forum/s...d.php?t=116926
It is the 'help' sheet that I recall but can't find. The absence of prose makes it almost as useless as not having it. A picture is worth 1000 words, but it seems, as I discovered, that none of them are printable!
Still, the wire brush treatment, suggested therein, is more logical.
Derek.