Not to allow Contributor users to access webpart menu of the webparts

Put this JavaScript just before “</BODY>”  on Master Page .

<script language="JavaScript">

    var doc = document.getElementsByTagName('ie:menuitem');
    for (var i = 0; i < doc.length; i++) 
    {
        itm = doc[i];
        if (itm.id.match('MSOMenu') != null) 
        {
            itm.hidden = true; 
        }
    } 
</script>

For More Option:

http://blogs.msdn.com/b/tejasr/archive/2010/03/26/not-to-allow-contributor-users-to-access-webpart-menu-of-the-webparts.aspx