If a base has been assembled... Sonic cannons set to match the resonance of bone with average porosity. Aim, fire, watch as zombies melt into still-living clumps of quivering muscle. Aim at hordes and run through several recommended bone-grinding frequencies until all hostiles are eliminated. If need be, the masses of flesh can be burned away with Lenin's flame-thrower. Sh'mon! We need tech! Who here is an expert at engineering and acoustics? Though without a permanent base and a generator (hand-pumped, if need be), such an effort would be fruitless.