Dispose the assets as you would normally do.
After you have ran your depreciation at month end, you will notice that your depreciation expense (FAS vs G/L) and accumulated depreciation (FAS vs G/L) would differ by the same amount. You will end up crediting your depreciation expense and debiting your accumulated depreciation by this amount. This is the amount of depreciation you had taken for not having disposed of the assets on 1/1/09.