Originally Posted by
Firebug4
Rub your fingertips across your forehead right before your put your fingers on the glass. The oil that is naturally present on the skin of your forehead will make the fingerprints stand out more prominently.
FB
When I went for my interview the CPB agent mentioned the "forehead trick", and I do this, but the last two times (of about 15) one or two fingers came up "marginal"--they were able to identify me from the other fingers, since I did
not get "X",