  CONTEXT. Many massive stars have nearby companions whose presence hamper
their characterization through spectroscopy. AIMS. We want to continue
obtaining spatially resolved spectroscopy of close massive visual binaries to
derive their spectral types. METHODS. We have used lucky spectroscopy to obtain
many short long-slit spectroscopic exposures of 19 close visual binaries under
good seeing conditions. We selected those with the best characteristics,
extracted the spectra using multiple-profile fitting, and combined the results
to derive spatially separated spectra. The results are analyzed in combination
with data from lucky imaging, regular intermediate-resolution single-order
spectroscopy, and \'echelle high-resolution spectroscopy. RESULTS. The new
application of lucky spectroscopy has allowed us to [a] spatially disentangle
for the first time two O stars (FN CMa B and 6 Cas B) with brighter BA
supergiant companions; [b] determine that two B stars (alpha Sco B and HD
164492 B) with close and more massive companions are fast rotators; [c] extend
the technique to cases with extreme magnitude differences, shorter separations,
and fainter primary magnitudes down to B=11; [d] spatially disentangle the
spectra of stars with companions as diverse as an A supergiant (6 Cas A), a WR
star (WR 157), and an M supergiant (alpha Sco A); [e] discover the unexpected
identity of some targets such as two previously unknown bright O stars (HD
51756 B and BD +60 544) and a new member of the rare OC category (HD 8768 A);
and [f] identify and classify which of the components of four visual binaries
is a double-lined spectroscopic binary and for another seven systems detect
signs of spectroscopic binarity using high-spectral-resolution spectroscopy. We
also present a determination of the limits of the technique. [ABRIDGED]
