To evaluate the feasibility of the recently proposed detection scheme of low energy neutrinos released from the Sun and supernovae, which relies on the transparency of noble-gas cryogenic liquids to VUV radiation, we analyze theoretically VUV emission, self-absorption, and scattering of liquid helium and neon, primary candidates for CLEAN. The emission spectrum is substantially shifted from the absorption spectrum, and the absorption is expected very small, allowing building large detectors. Our analysis, however, shows that the self-absorption and Rayleigh scattering are comparable to the size of the proposed detector. (c) 2005 Elsevier B.V. All rights reserved.