We present the formation of hydrated electrons by laser vaporization, and investigate in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer their destruction by the 300 K black body infrared background radiation. While clusters above n greater than or equal to 32 decay almost exclusively by fragmentation and loss of ligands, the smaller species also detach electrons, with the relative rates of the two processes exhibiting an interesting alternation. Below n=15 they almost exclusively detach electrons, and for n less than or equal to 12 the detachment rate is apparently so fast that no clusters are observed in the ICR-experiment. From n=19 to n=24 a pronounced odd-even alternation between electron detachment and fragmention is observed, which is tentatively attributed to entropic rather than energetic effects.