The list of supported applications is fairly limited, though, and extending it requires manually setting up custom rules. CCEnhancer is a small companion utility that greatly improves CCleaner by adding some 270 new programs in one fell swoop. The software makes use of the custom rules capabilities to add new third-party apps to the list, with most rules sourced from the Piriform Support Forum, and a few others from several other places around the web.
After downloading and running CCEnhancer (no install required), a click on 'Download Latest' in the main program window downloads the latest definition files and adds them to CCleaner. On next startup CCleaner will display the additional programs under Applications -- though only those that are installed will show up on the list, of course.
Users must have .NET 3.5 installed to use this program. Additionally, Windows Vista and 7 users must run CCEnhancer with admin privileges (right click -> Run as Administrator), otherwise the program just freezes while updating the rules.