I need to select what filter should appear for every category and sub category.
the problem is that if I leave all the filters in the parent categories  the website is too confusing to browse, also I have more than a filter with the same name in a single category.
After a lot of unsuccesfull attempts I've found that using :

    <reference name="catalog.leftnav">
    </reference><action method="unsetChild"><alias>category_filter</alias>
    </action>

in the custom design tab of every categories does the trick to remove the "category_filter" , so I would like to use it for removing other filters that I do not want.

This soultion could be perfect beacuse I have a complete control of what filter I wanted to show, and unset unwanted filters from viewing.

Unfortunately all the alias that I tried ( looking in the attribute menu and trying both 'attribute alias' and 'attribute alias_filter' ) are not working.
there is a way to discover the correct alias?
also, is this a correct way to do this?