  The epsilon-impurity of the K_L wave-function gives rise to a huge
CP-violating effect in the decay K_L -> pi^+ pi^- gamma which is hidden in the
polarization state (Stokes vector) of the photon. One component of the Stokes
vector is CP-odd and T-even, and may be identified with circular polarization.
Another component is CP-odd and T-odd (``oblique polarization'') and reveals
itself as a large asymmetry (14%) in the decay K_L -> pi^+ pi^- e^+ e^-.
Striking time-dependent effects are predicted in the angular distribution of
the pi^+ pi^- e^+ e^- system emanating from an initial K^0 or K^0bar state.
