I have a pivot table by that I update every month, by refreshing the query to
append the new data. It has data by customer and period, type of work, etc.,
with values for Parts, Labor, Tax, etc.

I was asked to strip out data to leave only information to send to a single
customer. I have removed all data from the source range except for that
belonging to that customer, but in the pivot table selection box for
customer, all of the other customers' names still appear. I have already
resaved the entire pivot table and reopened it, with the "refresh on open"
parameter checked, but they do not disappear. How do I get unused values to
drop from the list?