To remove quotes loop over the rows and use the substitute function.
dt = New Table( "Test Quote Removal", Add Rows( 4 ),
New Column( "Group", Character, "Nominal",
Set Values( {"A05", "\!"A06", "\!"A07", "A08"} )
)
);
for (i = 1, i <= nrows(dt), i++,
dt:group[i] = substitute(dt:group[i], "\!"", "");
);