Instructions
Nintendo Wii
Place an SD card into the SD slot on the front of the Wii. This slot is located underneath the disc slot.
Turn the system on using the power button.
Point at the "Wii Settings" icon using your Wiimote (the Wii's wireless remote control) and press "A."
Hover over the "Data Management" option and press "A" to select it.
Choose "Save Data" and then select "Wii" from the next screen.
Open the "SD Card" by pointing the Wiimote at that option and pressing "A."
Use the Wiimote to point at each file you'd like to delete. Press "A" to select that file, then point at the "Erase" button and press "A."
Xbox 360
Insert the memory card into your Xbox 360.
Power the system on by pressing the large circular button on the front of the console.
Navigate to the "My Xbox" option using the control pad and press "A."
Select "System Settings" from the My Xbox screen and press the "A" button.
Press down three times on the control stick to highlight the "Memory" option. Press "A" to select it.
Select the "MU" option and press "A." This will show you the data located on your memory card.
Open the category of content you'd like to erase from the memory card by moving up and down with the control stick and pressing "A."
Press "A" to open the settings page for any piece of saved data. You can then select the "Delete" option, which is the third one present.