Pivot Table Value Filter won't work

I'm using Excel 2007 to analyze sales data for my territory managers. My database is 21 columns by 39,078 rows (in case this matters.)
My pivot table will not allow me to use the value filters - all options are greyed out except "top 10". I need to be able to exclude the accounts with zero sales dollars. How can I get the value filter option to work for me?