You can have your Tax Free Form stamped for export validation at the service point on the first floor of the arrivals hall, opposite the taxi station.
Fill in the required details on the form, including your passport number, name, address and credit card number. Drop off the stamped Tax Free Form in a Planet refund box.
If the service point is closed, you can have your Tax Free Form stamped for export validation by Finnish Customs. Customs service points are located on the first floor of the arrivals hall, opposite the taxi station, and near gate 29.