How to Delete Skype Chat
Skype is a communication program that allows you to instant message, voice chat and make calls to family and friends all around the world. By default, Skype keeps a record of your chats so you can review them anytime you want. However, if you are no longer interested in this feature, you can clear your Skype chat history in just seconds on a Mac or a PC.
Launch Skype and log onto your account using your screen name and password.
Click the "Skype" (Mac users) or "Tools" (Windows users) menu and click "Preferences" or "Options" to launch the Skype options screen.
Click the "Chat" tab (Mac users) or "Privacy Settings" (Windows users). Click the "Clear History" button to clear your Skype chat history. Click "Delete" in the confirmation dialog box.