  Isolating the scattering of longitudinal weak bosons at the LHC is an
important tool to probe the ElectroWeak Symmetry Breaking mechanism. Separating
polarizations of $W$ and $Z$ bosons is complicated, because of non resonant
contributions and interference effects. Additional care is necessary when
considering $Z$ bosons, due to the $\gamma/Z$ mixing in the coupling to charged
leptons.
  We propose a method to define polarized signals in $Z\!Z$ and $W^+\!Z$
scattering at the LHC, which relies on the separation of weak boson
polarizations at the amplitude level in Monte Carlo simulations.
  After validation in the absence of lepton cuts, we investigate how polarized
distributions are affected by a realistic set of kinematic cuts (and neutrino
reconstruction, when needed). The total and differential polarized cross
sections computed at the amplitude level are well defined, and their sum
reproduces the full results, up to non negligible but computable interference
effects which should be included in experimental analyses. We show that
polarized cross sections computed using the reweighting method are inaccurate,
particularly at large energies. We also present two procedures which address
the model independent extraction of polarized components from LHC data, using
Standard Model angular distribution templates.
