CCleaner doesn't "Reset" the size of index.dat files for IE

If you use Internet Explorer, after cleaning with CCleaner and even a reboot, you can still find the index.dat files with large size. They will continue to grow and record your internet activities when surfing on the Internet. This will take your valuable disk space day after day. Why does CCleaner not take care of this situation?

On Windows 7:

C:\Users\YourName\AppData\Local\Microsoft\Windows\Temporary Internet Files\index.dat

C:\Users\YourName\AppData\Roaming\Microsoft\Windows\Cookies\index.dat

C:\Users\YourName\AppData\Local\Microsoft\Windows\History\index.dat

What size are they? The index.dat files on my sys are around 32 - 48 mb, and that's after four years of CC maintenance. I am on XP though.