Send a mail to "o-info-request@kaktus.kemi.aau.dk" with "Unsubscribe" in the SUBJECT field. Do NOT send this to o-info@kaktus.kemi.aau.dk !!!

Naturally, all of this can be done with an O macro as well

 ! unsubscribe.omac
 !
 $ Mail -s unsubscribe o-info-request@kaktus.kemi.aau.dk < /dev/null
 bell print Your o-info nightmare will be over soon