Pivot Table

once you have created a pivot table, and then for example you want to enter a £ sign in one of the columns eg. column C, it lets you do this but then if you filter the pivot table to anything else, the £ sign disappears and you have to insert this into the range again, any way to make this stay in the higlighted column you have chosen without disappearing when filtered, as this does not happen in a normal work sheet?? thanks