clearing the shear key of water before grouting

[dudesteel]

hi, all

I was wondering if anyone has a good method to remove water from a pedestal shear key pocket after the column has been installed.
The base plate is roughly 6x3ft with a double shear key.

Also I'm getting lots of different answers about if that water were to freeze would it pop the pedestal. I think if the key is open to air the ice would freeze up correct? (in reference to a shear key with a column erected full of water)

Thanks
DS