1
The powder is shaving talcum with the secret ink ingredient mixed in it.
2
I'm sure you know all about secret ink.'
3
About secret ink he tells us:
4
There is enclosed a bottle of secret ink powder which you requested in connection with your North Africa-Near East operation.
5
These authors frequently allude to their use of red, black and secret inks.
6
'I thought I'd at least learn some interesting gadgets, like using secret ink.
7
" Secret ink?" Viv said, peering at the memo.