Clear log in Chat 

The clear window hyperlink in the chat box does not get rid of your messages.

It just clears the window. Your chats are still listed in Facebook so if there is a chat you don't want a record of, you will need to clear the window but also go into the conversations and delete them from there. I believe this is a new feature in Facebook. I don't think everyone has it yet. When you get the feature your old messages will still be there (even after clicking clear window from the past. Another words, if six months ago, you clicked clear window, your messages are still on Facebook till you delete the conversation list). To delete the messages do the following

1. Click Clear Window

2. Click the box on the bottom right of the chat window (I have it highlighted in yellow)

3. Click Actions

4. Click Delete Messages...

5. Check the ones you want to delete

6. Click Delete Selected

You will also need to clear the conversations in the chat window. To clear the chat window click here for instructions.

Note: Clearing the Clear window removes the chats from the chat window only but doesn't clear the conversation history. Same goes with the conversation history window. If you clear the conversation window but do not click the Clear Window hyperlink in the chat, the text in chat will still be there even though you cleared it on the conversation history. You have to clear both for it to be gone.