CCleaner Portable is the best free file cleaner around and is portable so you don't have to install it on your computer. It cleans very well for a free app and even has a registry cleaner built in. You do however have to be careful the options you choose to use as some can hurt the way your computer runs. If in doubt just use the default settings.

The only complaint I have about CCleaner Portable is it needs to make it's registry cleaner better. Outside of that I really don't have any complaints.

So if there is anyone who wants a free portable alternative to Window Washer then give CCleaner Portable a try.