To delete all messages contacts fail. You can delete correspondence one friend, then move on to another. To do this, log on its page in "Schoolmates". In the main menu scroll to "Messages". Clicking on it mouse button you will be redirected to the page with his correspondence.
If you have a lot of friends, finding the right person can be simplified, scoring in the search line the name of the addressee, the correspondence with which you decided to remove. If friends so much, you can use the vertical slider to locate the user. Click on the photo of your "friend". Opened your message history. At the top click where it says "Delete entire conversation". In the window that appears, confirm your actions by clicking on the "delete" button. Now if you want you can start communicating again with a clean slate.
Perhaps you will find that can delete an entire conversation is not necessary, but some messages you hate to read. In this case, remove only unwanted messages. For this opposite message, claiming the removal, find a cross that says "Delete message". A window will appear asking where you must confirm your action by pressing the "delete"button.
In a social network "Schoolmates" is a function, which include you will be able to protect themselves from unwanted messages. Despite the fact that your profile will remain open, and accordingly, you will remain open to communication with both new and old friends. But the messages unpleasant content from people who are not your friends, will no longer bother you.
Menu under your photo, scroll to "More". Clicking it with the mouse button, go to "Change settings". Select the line "Settings of publicity." Under "Allow" find the line "Write me" message. Check the box "Only friends". You will now be able to receive messages only from friends.