Instructions
Turn on your PlayStation 3 and select "Game Data Utility."
Highlight the patch you want to delete. For example, the patch should read "Modern Warfare 2."
Press "Triangle" and select "Information" to verify this is the patch you want to delete. Many games require installation, and this is a separate thing from the patch. Game installations tend to be more than 100 megabytes, and they are frequently larger than one gigabyte. Patche files are typically less than 100 kilobytes, and save games are in an entirely different section.
Press "O" to exit the information menu. Select "Delete" when you find the correct entry.