The Polish Mill is
used for cleaning out the IDs of the components at the liner top like the Polished Bore Receptacle or the tieback Polished Bore Receptaclein order to
ensure that the wellbore is clean before reinstalling the completion string. Usually, as a minimum
configuration it consists of a Tie Back Mill, a spacer to match the PBR length, and
a Top Dressing Mill.
Surface cleaning without destroying the honed surface structure of the PBR