Bono snorts salt to aid his singing voice.
The 'With or Without You' singer regularly sniffs salty water as it acts as an antiseptic for his throat and helps ensure he can hit high notes, according to The Script frontman Danny O'Donoghue.
Danny told Britain's Daily Mirror newspaper: "Snorting salts - it's actually a singing technique.
"Myself and Bono share a vocal coach. Whenever the high notes aren't feeling that high or in the morning you're groggy, you snort salt water up your nose.
"It cleans out cavities, it's a natural antiseptic for your throat."
Bono recently praised his U2 bandmate The Edge, claiming he is the most influential guitarist since Jimmy Page.
Writing in response to a near-perfect review of the reissue of the band's 1980 debut album, 'Boy', Bono said: "Edge's genuine genius developing on the blank and bleached photographic paper avoiding all the obvious blues scales that blind every other guitar player that ever heard Led Zeppelin.
"The Edge finds some new colours for the spectrum of rock."