Mac OS X 10.6: Removing files and folders from your computer
You can delete files, folders, and other items that you no longer need.
You may want to store a backup copy or an archive of important items if you are trying to clear space on your internal disk.
To remove an item:
Drag it to the Trash. The Trash is located at the end of the Dock.
If you change your mind, click the Trash icon to open it, and then drag the item out of the Trash or select the item and choose File > Put Back.
You can’t put locked items in the Trash. To unlock an item, select it and choose File > Get Info, then deselect the Locked checkbox in the General pane. If you do not own the item, you may need to provide an administrator’s name and password to put the item in the Trash.
Choose Finder > Empty Trash.
Important:Even after you empty the Trash, deleted files can be recovered using data-recovery software. To delete files so they can’t be recovered, choose Finder > Secure Empty Trash. Files deleted in this way are completely overwritten by meaningless data. This may take some time, depending on the size of the files.
When you see a warning message, click OK.
To prevent the warning message from appearing, press the Option key when you choose Empty Trash. You can also turn off the warning in the Advanced pane of Finder preferences.
To prevent the recovery of files you deleted previously, open Disk Utility, choose Help > Disk Utility Help, and search for help on erasing free disk space.