CCleaner will clean many Windows logs like WindowsUpdate.log, etc., but it can't do it in the normal Windows mode. You have to log into Safe Mode to get rid of those files because their host application won't be running to lock them out from cleaning utilities like CCleaner.
I forgot, the file "WINNT/ShellIconCache" holds all the icons cache on your computer. There are many free icon flushers/refreshers available such as Microsoft's Tweak UI.
CCleaner will clean many Windows logs like WindowsUpdate.log, etc., but it can't do it in the normal Windows mode. You have to log into Safe Mode to get rid of those files because their host application won't be running to lock them out from cleaning utilities like CCleaner.
Locked files can also be deleted on the next reboot by using freeware software such as Unlocker by Cedrick Collomb (http://ccollomb.free.fr/unlocker) or DelNext by Gammdayne (http://gammadyne.com/cmdline.htm). For my own use, both of these have proven to be very successful for deleting locked files, including those already mentioned and index.dat files.