Method 1: First save the file in dxf format, then reopen CAD, open the newly saved file in dxf format and save it in dwg format, so as to remove the production mark of Autodesk Education Edition when printing.

Method 2: Convert to R 14 by other dwg version conversion tools (such as AcmeCADConverter).

Method 3: Save it as a DWT template file, open it and save it back to DWG.