  When studying subgroups of $Out(F_n)$, one often replaces a given subgroup
$H$ with one of its finite index subgroups $H_0$ so that virtual properties of
$H$ become actual properties of $H_0$. In many cases, the finite index subgroup
is $H_0 = H \cap IA_n(Z/3)$. For which properties is this a good choice? Our
main theorem states that being abelian is such a property. Namely, every
virtually abelian subgroup of $IA_n(Z/3)$ is abelian.
