From Robert Moerland:
Disk Cleaner is a free open source tool to quickly and easily clean your hard disk from temporary files like those in the system temporary folder, the Internet Explorer Cache and Cookies folder, and the Recycle Bin. Disk Cleaner is focused on ease of use, speed and a small size, both when downloading and when installed. It is fast, since the crucial parts are written with just the plain Windows API giving high search and remove performance. Disk Cleaner is also entirely self-contained: no other (large) DLLs are necessary to run the application, so it can even be run from a floppy without trouble. Handy to remove your junk from public machines.