You probably have heard if you put files and folders in the trash that it does not mean the files are really gone. Even emptying the trash doesn’t get rid of files permanently.

To prevent most anyone from recovering the files you have deleted, you need to securely delete your files as you remove them and occasionally wipe your machine’s free space.

They are both very easy to do.

To start with, we first need to set up the secure deletion of files and folders.

If you have a PC, you will need to download a open source (free) program called ERASER from here. I’ve used this program for years, and it has never given me any trouble in Vista, XP or even the new Windows 7.

Once you have ERASER downloaded, double click the program and let it install.

After it has installed, the first extra option ERASER has put on your PC will appear whenever you right click on any file. You should see a new ERASE option. If you choose ERASE, that file or folder you clicked on will be securely shredded beyond recovery!

If you want to be ultra secure, after you click on ERASE, the pop-up menu that appears has an OPTIONS button. You can click it and choose other options that are more secure than the basic setting, but each higher setting will take around triple the amount of time as the one before it. The first setting is secure enough, so leave it at “1 Passes” (or “3 passes”) and click OK.

If you are on a Mac, you don’t need to install anything to securely shred your files. When the folders and files you want to get rid of are in the trash, click on the FINDER icon in your dock, then go to the FINDER menu on the top menubar and choose SECURE EMPTY TRASH. This second setting, under the regular “empty trash” command, will securely shred your documents beyond recovery, just like ERASER did for the PC.

Wiping space on your hard drive is the second step in basic data security. Wiping the free space on your hard drive will delete any stray files that were previously on your system that were moved but still recoverable, as well as any temporary files that have yet to be overwritten. The only problem is that wiping the free space on your Mac or PC will tie up your machine for a few hours. I usually set up the process for once a month on a random Sunday, start it in the morning, and by midday it is done.

ERASER has the ability to wipe the free space on a PC’s hard drive, while Mac users have this feature built in.

To wipe the free space on a PC after you have installed ERASER, go to MY COMPUTER. Now right click on the C drive and go to ERASE UNUSED SPACE in the pop up menu. A dialog box will appear asking you “are you sure you want to erase unused space on drive C:\?” Say YES and that’s it!

Just like on the single file and folder erasing, after you click on ERASE UNUSED SPACE the pop-up menu that appears has an OPTIONS button. You can click it and choose other options that are more secure than the basic setting, but each higher setting will take around triple the amount of time as the one before it. The first setting is secure enough, so leave it at “1 Passes” (or “3 passes”) and click OK. That’s it!

To wipe the free space on a Mac, you need to open your hard drive, open the APPLICATIONS folder and open the UTILITIES folder.

Once you are in the UTILITIES folder, look for DISK UTILITY and open that application. Once DISK UTILITY is open, click on your hard drive’s icon on the left column. Now on the right area, choose the ERASE tab.

Near the bottom of the ERASE tab, there is a button that says ERASE FREE SPACE. Once you click on it you will have three options on how securely you want to erase your free space. Each option is more secure than the other, but each higher setting will take either 7 or 32 times the amount of time as the one before it. The first setting is secure enough, so leave it at the top setting and click OK. That’s it!

Experiment a little to see how much time higher settings take to wipe the free space on your hard drive. I have mine set for 7 passes if I am going to be gone for the weekend and even higher when I actually get vacation time and can leave them running for prolonged periods.

Deleting your files securely and wiping free space on your hard drives is a great way to stay safe on your daily work and/or home machines. And even if you trash files normally on a day to day basis, wiping the free space on your hard drive will clean up all those regularly deleted files and keep you just as secure as if you has chosen to securely delete each file or folder individually.