A Vacuum Card Piece is a Card Piece that you can obtain from Collecting. There are 3 types of Vacuum Cards: 2%, 4%, and 7%. You need 10 of one type of Vacuum Card, by going to a Collecting Manager and having him transform them. He will make the Card which has the same % as the Piece. Vacuum Card Pieces give you only FP%+ Cards.
Go to a Collecting Area, and buy a Collector from a Collecting Manager. Then going into the Collecting Area with your Collector equipped. Then click Start on the box that pops up when you have a Collector equipped. You will then start Collecting.