Something

alias dchan {
  if (!$1) { 
    set %favchans $remtok(%favchans,$active,1,46)
    echo -a Deleted $active from auto join.
  }
  else {
    if ($1 == all) {
      var %delall = 1
      while ($numtok(%favchans,46) >= %delall) {
        echo -a Deleted all channels from the autojoin.
        set %favchans $deltok(%favchans,%delall,46)
        inc %delall
      }
    }
    else {
      set %favchans $remtok(%favchans,$1,1,46)
      echo -a Deleted $1 from auto join.
    }
  }
  return %dchan
}