  In most sociophysical simulations on public opinion, only two opinions are
allowed: Pro and Contra. However, in all political elections many people do not
vote. Here we analyse two models of dynamics of public opinion, taking into
account Indifferent voters: {\it i)} the Sznajd model with symmetry Pro-Contra,
{\it ii)} the outflow one move voter model, where Contra's are converted to
Indifferent by their Pro neighbours. Our results on the Sznajd model are in an
overall agreement with the results of the mean field approach and with those
known from the initial model formulation. The simulation on the voter model
shows that an amount of Contra's who remain after convertion depends on the
network topology.
