in reply to How do I uncheck a checkbox with WWW::Mech?

The documentation for WWW::Mechanize says tick and untick accept the following parameters:

$mech->tick( $name, $value [, $set] )

$mech->untick( $name, $value )

I therefore suspect that what you really need to do is the following:

$self->{'agent'}->untick('newsletters', 17); $self->{'agent'}->untick('newsletters', 65); $self->{'agent'}->untick('newsletters', 34); $self->{'agent'}->untick('newsletters', 71);
Or more succiently
$self->{'agent'}->untick('newsletters', $_) for (17, 65, 34, 71);

However, not knowing the form or the html that you're accessing, I can't say for sure what you're doing incorrectly. Can only go on the way it looks.