  We study coarsening phenomena in three different simple exclusion processes
with quenched disordered jump rates. In the case of the totally asymmetric
process, an earlier phenomenological description is improved, yielding for the
time dependence of the length scale $\xi(t)\sim t/(\ln t)^2$, which is found to
be in agreement with results of Monte Carlo simulations. For the partially
asymmetric process, the logarithmically slow coarsening predicted by a
phenomenological theory is confirmed by Monte Carlo simulations and numerical
mean-field calculations. Finally, coarsening in a bidirectional, two-lane model
with random lane-change rates is studied. Here, Monte Carlo simulations
indicate an unusual dependence of the dynamical exponent on the density of
particles.
