  The disordering of an initially phase segregated system of finite size,
induced by the presence of highly mobile vacancies, is shown to exhibit dynamic
scaling in its late stages.
  A set of characteristic exponents is introduced and computed analytically, in
excellent agreement with Monte Carlo data. In particular, the characteristic
time scale, controlling the crossover between increasing disorder and
saturation, is found to depend on the exponent scaling the number of vacancies
in the sample.
