There are instructions here for clearing old items from a pivot table:

http://www.contextures.com/xlPivot04.html

mikeg22 wrote:
I have set up a pivottable that relies on data in another worksheet.
When I put new data in to the data worksheet, the field's old values
stay in the filter dropdown list on the pivottable. I want to know how
to clear these values out so that only values that exist in the data
are available to filter on.

--
Debra Dalgleish
Contextures
http://www.contextures.com/tiptech.html