Joe used an app called Clean My Mac to do some spring cleaning. Leo says it's a good program and works just fine. Avoid MacKeeper, but Clean my Mac is fine. But there are some things on the Mac he doesn't know what they are. Leo adds that isn't common. All computers have files that he won't know what they are, but they are important for the operating of the computer. So don't be overly aggressive. That'll cause problems.