  We present a scaling view of underscreening observed in salt solutions in the
range of concentrations greater than about 1M, in which the screening length
increases with concentration. The system consists of hydrated clusters of
positive and negative ions with a single unpaired ion as suggested by recent
simulations. The environment of this ion is more hydrated than average which
leads to a self-similar situation in which the size of this environment scales
with the screening length. The prefactor involves the local dielectric constant
and the cluster density. The scaling arguments as well as the cluster model
lead to scaling of the screening length with the ion concentration, in
agreement with observations.
