It was rather shocking to find 2900 folders located in Internet Explorer's DOMStore that CCleaner doesn't clean. I'd like to suggest cleaning that area since it's been a part of Internet Explorer since IE8.
The path (on WinXP at least):
C:\Documents and Settings\User Profile Name\Local Settings\Application Data\Microsoft\Internet Explorer\DOMStore
Hmm. If you select (and clean) cookies then the DOMstore folder is cleaned automatically by CC, or it is in Win8/IE10. It still leaves those 8IKAQNHY-named folders - now empty. I only have four anyway (and an empty container.dat) so it's no prob. Is this what you mean or are yours filled with data?
Win8 path is C:\Users\Me\AppData\LocalLow\Microsoft\Internet Explorer\DOMStore, a hidden protected system folder.
Out of those 2900 folders some contained data. CCleaner has never once cleaned that folder on my system simply by going by some of the dates on many of those folders since I've had IE8 installed, also this is when using an Admin account on WinXP SP3.
This is the reason for the below temporary winapp2.ini cleaner I made so others with the same issue can clean that folder. Perhaps this is also the reason for all those bug reports by people stating websites remembering their info via some persistent cookie since DOMStore is "similar to HTTP cookies" but can instead store almost 10x more data.
For those wondering what DOMStore is view this Microsoft article:
I made this winapp2.ini cleaner for it in the meantime, it can be found under:
Cleaner > Applications -> Internet Explorer
[DOMStore*]
LangSecRef=3001
Detect=HKCU\Software\Microsoft\Internet Explorer
Default=False
FileKey1=%LocalAppData%\Microsoft\Internet Explorer\DOMStore|*.*|RECURSE
Edit:
Note: If that folder is full of folders/files like mine was do expect CCleaner to take a good amount of time to clean it (even with secure delete modes turned off), CCleaner may even act as if it's frozen like it did on my system for a few minutes.