This procedure explains how to uninstall Skype on a Mac running OS X.
You can use AppCleaner, a free utility allowing you to uninstall applications from your Mac. AppCleaner will automatically delete residual files or folders that may result from the uninstallation of programs, keeping your system clean from obsolete junk files. If you are looking for another software but with more features, then Clean My Mac is the most sensible choice (available as a free or paid version).
ApplCleaner and Clean My Mac are not available on the Mac AppStore, but they can be downloaded from their respective official websites. Prior to the downloading and installation of such software, you need to configure the Gatekeeper settings: Run Apps Downloaded From Unknown Sources.
You can also manually remove Skype from your system. Go to the Application folder and drag the Skype application to the trash folder. Perform the same operation for the Skype folder, located at Drive/Users/username/Library/Application Support/Skype.