Instructions
Turn the PS2 on. Remove any games or DVDs from the disc tray. This will bring you to the PS2 home menu.
Insert the memory card that you want to erase. Select this memory card when it comes on the screen by pressing the X button. You will be presented with a list of saved content on the memory card.
Select "Format." Select "Yes" when asked to confirm. This will erase all of the data on your memory card.