  NACO is the famous and versatile diffraction limited NIR imager and
spectrograph with which ESO celebrated 10 years of Adaptive Optics at the VLT.
Since two years a substantial effort has been put in to understanding and
fixing issues that directly affect the image quality and the high contrast
performances of the instrument. Experiments to compensate the non-common-path
aberrations and recover the highest possible Strehl ratios have been carried
out successfully and a plan is hereafter described to perform such measurements
regularly. The drift associated to pupil tracking since 2007 was fixed in
October 2011. NACO is therefore even better suited for high contrast imaging
and can be used with coronagraphic masks in the image plane. Some contrast
measurements are shown and discussed. The work accomplished on NACO will serve
as reference for the next generation instruments on the VLT, especially those
working at the diffraction limit and making use of angular differential imaging
(i.e. SPHERE, VISIR, possibly ERIS).
