  Possible signals for indirect CPT violation arising in experiments with
neutral kaons are considered in the context of a general CPT- and
Lorentz-violating standard-model extension. Certain CPT observables can depend
on the meson momentum and exhibit sidereal variations in time. Any
leading-order CPT violation would be controlled by four parameters that can be
separately constrained in appropriate experiments. Recent experiments bound
certain combinations of these parameters at the level of about $10^{-20}$ GeV.
