CCleaner (Piriform) has been taken over by Avast, a commercial antivirus concern. It is said that the more recent iterations of CCleaner are no longer as clean and best avoided.What do you recommend?
I use BleachBit, which is a free and open-source alternative. It has not caused me any grief.
ETA: It is probably a good deal more thorough than CCleaner and for this reason it should be used with a little care by new users until they become comfortable with it. Create a restore point before use and take notice of what check boxes you're ticking. Don't just automatically tick everything.