How to empty the editor after a insertHTML() ajax call

Hi all,

i have a instance of CKEditor 4.0.1 which is populated by an Ajax call with .insertHTML() after a click on some text. Works great, but If I click that text again it appends it after the former Ajax inserted text. Normal behaviour, but I want the second text to replace the first. Therefore I think i have to empty the contents of the editor, but how?

Been looking for two days now and just can't seem to find the solution :(