metamail-switches

metamail-switches is a variable defined in `metamail.el'.
Its value is

("-x" "-d" "-z")

Documentation:
Switches for `metamail' program.
`-z' is required to remove zap file.
It is not expected to be altered globally by `set' or `setq'.
Instead, change its value temporary using `let' or `let*' form.
`-m MAILER' argument is automatically generated from the
`metamail-mailer-name' variable.

You can customize this variable.