To an extent Keith. However, a transformer is not the most efficient way to get rid of DC. It obviously depends on the extent of the problem, but the DC will affect a 1:1 transformer in exatly the same way as any other. The worst condition is under low or zero current load, when a transformer is most susceptible to DC, when even a small amount can cause a significant partial saturation. Basically therefore, the isolation transformer will be as susceptible to mechanical buzzing as anything downstream. The bigger the transformer (in terms of current capacity) the worse the issue, as the resistance is lower. Therein lies the problem. A small transformer will work OK, because the winding resistance is higher, but a small transformer won't be suitable for isolation of power amps or the like, which are also the most likely to be affected in the first place.
A capacitor on its own will block DC and pass AC, but a suitably large value capacitor capable of handling the voltage is impractical. The best possible method uses diodes, capacitors and a couple of resistors. I won't give the circuit here for obvious reasons