wp_nav_menu remove class and id from li

I’m new to wordpress and trying to learn my way through from making a theme.
Right now I am using wp_nav_menu to generate my menu
My menu consists of pages and categories

However, the default generation of the menu looks like

<div id="navi">
<div class="menu-primary-container">  
  <ul id="menu-primary" class="menu">
    <li id="menu-item-14" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-14"></li>
    <li id="menu-item-16" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-16"></li>
    <li id="menu-item-20" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-20"></li>
    <li id="menu-item-15" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-15"></li>
    <li id="menu-item-17" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-17"></li>
  </ul>
</div>
</div>

I want to remove all the class and id from li and ul. I have been googling for awhile now. Tried different methods and no luck. Any help would be much appreciated. I’m currently using WordPress 3.1

Thank you in advance!

If you look in the wp_nav_menu() function, you see the items are written by walk_nav_menu_tree(), which calls Walker_Nav_Menu to do the work (unless you specified your own walker class). This class contains a method start_el() that is called for each menu item. In this function, you see that the classes are filtered through nav_menu_css_class and the id is filtered through nav_menu_item_id. So if you attach your own code to these hooks, you can change them to anything you want.

Submenus are always wrapped with <ul class="sub-menu">, the main wrapper can be changed via the menu_id and menu_class arguments.