A hybrid-heating microwave oven provides the energy to heat small 10-gram samples of spent metal tritide storage bed material to release tenaciously held decay product 3He. Complete mass balance procedures require direct measurement of added or produced gases on a tritide bed, and over 1100°C is necessary to release deep trapped 3He. The decomposition of non-radioactive CaCO3 and the quantitative measurement of CO2 within 3% of stoichiometry demonstrate the capabilities of the apparatus to capture generated (released) gases.