The intriguing mystery of ultra-high energy (UHE) cosmic particles is the nature of their sources. In this presentation we indicate how these UHE particles, in order to uncover their sources, can be detected using radio observations of the Moon. When high-energy cosmic rays impinge on a dielectric, such as the lunar regolith, radio waves are produced through the Askaryan effect. At wavelengths comparable to the length of the shower produced by an UHE cosmic ray or neutrino, radio signals are an extremely efficient way to detect these particles. First results of observations obtained with the Westerbork Synthesis Radio Telescope will be reported, already showing improved flux limits for neutrinos with energies in excess of 3 10²² eV. The status of the planning of similar observations with LOFAR will be presented.