Hark! I heard "Felice Friese" > say:

> From the Don't Laugh Until You've Tried It file: Sing, loud and strong, as
> you chop. It helps to use a song with a lot of verses (I do "Battle Hymn of
> the Republic" or "Onward, Christian Soldiers").
>
> Well, it works for me. There's probably a pseudo-scientific explanation, but
> I'm damned if I know what it is.

Maybe because when you sing, you're breathing through your mouth rather
than nose? Heck if I know...

J.J. - who luckily doesn't have trouble with onion tears...