To manage databases:
Choose Safari > Preferences, and click the Security tab.
To increase or decrease the amount of space initially available for databases: Open the “Default space for database storage” menu and choose an amount. If a website subsequently requires additional space, a prompt will appear on your screen.
To view or remove databases, click Show Databases: You can highlight one or more databases to remove, or remove all of them.
Important: If you remove a database, all the information in it is removed. Your website service may not be able to retrieve your information.