when cc cleans temp files and cookies. where do they go? permanantly erased?
Hi castro, and welcome to the forum.
I suppose technically, they don't go anywhere.
In CCleaner/Options/Settings, if you select "Normal File Deletion", then the file itself isn't deleted, but the MFT (Master File Table) registers the area it occupied as now being free space, to be overwritten if and when that space is needed.
If you select "Secure File Deletion", with a Simple Overwrite (1Pass), then the file is actually overwritten by CCleaner, and this is all you would require in normal circumstances.
The Beginners Guide (link in my signature), is well worth reading.