It sounds as though you changed the code in inc/toolbar.php. If so, you would be better off using an action plugin which removes the buttons that you don't need. That way, when you update Dokuwiki to the next release, you will not loose your settings.
See:
https://www.dokuwiki.org/devel:action_plugins
This function, for instance, will remove bold, italic and underline:
function delete_buttons(& $event, $param) {
for($i=0; $i<count($event->data); $i++) {
if($event->data[$i]['key'] == 'b' || $event->data[$i]['key'] == 'i' || $event->data[$i]['key'] == 'u') {
unset($event->data[$i]);
}
}
}