  Classical entanglement is a powerful tool which provides a neat numerical
estimate for the study of classical correlations. Its experimental
investigation, however, has been limited to special cases. Here, we demonstrate
that the experimental quantification of the level of classical entanglement can
be carried out in more general instances. Our approach enables the extension to
arbitrarily shaped transverse modes and hence delivering a suitable
quantification tool to describe concisely the modal structure.
