CCleaner not removing index.dat files?

Hi,

When I let CCleaner analyse my disks it will find .dat files. However those .dat files always appear to be 0kb; so without content. But when I run Defraggler I am amazed to find defragmetated .dat files there that "weigh" many MB's...

I draw the conclusion that CCleaner finds .dat files but doesn't delete them. Am I right?

1) index.dat files are deleted (at system restart) but the system then recreates them (removing them is akin to vacuming them empty)