custom filter layered navigation

I need to manage the attributes that are in the layered navigation. The reason is that in the parent categories there are a lot of attributes that I don't want and could confuse customers. Basically it's very simple, in the "custom design" of the categories I need to add the code to unset the attributes that I do not need. I tried to do by myself , but I only was able to remove the "category" filter. Other attributes are still there, and every time I try to unset them all the layered navigation is completely messed up. Website in magento 1.9.0.1 Custom template installed. The line of code should be added in the categories "custom design" so I can change or remove other new attributes that I may add to the website. Custom lines of code added by me are needed to remove the "category_filter" under the "Filter products by" column.