If your PC is running low on space and its performance is gradually decreasing then it is time to run a disk cleaner. A good option was CCleaner but it is a paid product now. CCleaner best alternative is BleachBit. BleachBit is Open Source and free to use in windows and Linux Operating System. BleachBit is available freely to download from here.
Free lost of disk space
Reduce Backup creating time and cost to save backup by removing un-necessary files
Increase system performance by clearing cached files of common web browsers.
Delete your private files completely by overwriting them
Built in shredder to for un-recoverable files.
Simple operation and greater control read the descriptions and authorize only those operation that you required.
No spyware or adware is included.
Command line interface for use in other applications.
Translated in 65 languages.
BleachBit is available for Ubuntu, Centos, MAC OSX and Windows