  We describe measurements of spin-polarized tunnelling via discrete energy
levels of single Aluminum grains. In high resistance samples ($\sim G\Omega$),
the spin-polarized tunnelling current rapidly saturates as a function of the
bias voltage. This indicates that spin-polarized current is carried only via
the ground state and the few lowest in energy excited states of the grain. At
the saturation voltage, the spin-relaxation rate $T_1^{-1}$ of the highest
excited states is comparable to the electron tunnelling rate: $T_1^{-1}\approx
1.5\cdot 10^6 s^{-1}$ and $10^7s^{-1}$ in two samples. The ratio of $T_1^{-1}$
to the electron-phonon relaxation rate is in agreement with the Elliot-Yafet
scaling, an evidence that spin-relaxation in Al grains is governed by the
spin-orbit interaction.
