  An approach is introduced for incorporating the concept of stellar pollution
into stellar evolution models. The approach involves enhancing the metal
content of the surface layers of stellar models. In addition, the surface
layers of stars in the mass range of 0.5-2.0 Solar masses are mixed to an
artificial depth motivated by observations of lithium abundance. The behavior
of polluted stellar evolution models is explored assuming the pollution occurs
after the star has left the fully convective pre main sequence phase. Stellar
models polluted with a few Earth masses of iron are significantly hotter than
stars of the same mass with an equivalent bulk metallicity. Polluted stellar
evolution models can successfully reproduce the metal-rich, parent star tau
Bootis and suggest a slightly lower mass than standard evolution models.
Finally, the possibility that stars in the Hyades open cluster have accreted an
average of 0.5 Earth masses of iron is explored. The results indicate that it
is not possible to rule out stellar pollution on this scale from the scatter of
Hyades stars on a color-magnitude diagram. The small amount of scatter in the
observational data set does rule out pollution on the order of 1.5 Earth masses
of iron. Pollution effects at the low level of 0.5 Earth masses of iron do not
produce substantial changes in a star's evolution.
