How do you get rid of a virus on your phone? How do I get more space on my phone? How can I add more memory to my android? What does clean master do? Our phones are full of old files, apps, pictures, and other content that we don't even look at anymore. Anyone who owns an older Android phone or just puts a lot of stuff on their smartphone could probably benefit from some spring cleaning. The Clean Master app is one of the most popular phone cleaners, and it even comes pre-installed on select phones. CleanMaster has an impressive 4.5 star rating average, which is based on 31 million reviews, so you know it's got to be good. The question is, do you know how to use it to your best advantage? Clean Master is a comprehensive, but confusing app, so we've put together a guide on how to get the most from it.