  We carry out a detailed strong lensing analysis of a sub-sample of eight
galaxy clusters of the CLASH survey, in the redshift range of $ z_{\rm cluster}
= [0.23-0.59]$, using extensive spectroscopic information, primarily MUSE
archival data complemented with CLASH-VLT redshift measurements. Different
models are tested in each cluster depending on the complexity of its mass
distribution and on the number of detected multiple images. Four clusters show
more than five spectroscopically confirmed multiple image families. In this
sample, we do not make use of families that are only photometrically
identified, in order to reduce model degeneracies and systematics due to the
potential misidentifications of some multiple images. We present spectroscopic
confirmation of 27 multiply lensed sources, with no previous spectroscopic
measurements, spanning over the redshift range of $z_{\rm src}=[0.7-6.1]$.
Moreover, we confirm an average of $48$ galaxy members in the core of each
cluster, thanks to the high efficiency and large field of view of MUSE. Despite
having different properties (i.e., number of mass components, total mass,
redshift, etc), the projected total mass and mass density profiles of all
clusters have very similar shapes, when rescaled by independent measurements of
$M_{200c}$ and $R_{200c}$. Specifically, we measure the mean value of the
projected total mass of our cluster sample within 10 (20)% of $R_{200c}$ to be
0.13 (0.32) of $M_{200c}$, with a remarkably small scatter of 5 (6)%.
Furthermore, the large number of high-z sources and the precise magnification
maps derived in this work for four clusters add up to the sample of
high-quality gravitational telescopes to be used to study the faint and distant
Universe. The strong lensing models and the full redshift catalogues from MUSE
are publicly available.
