How can I get range strings from cell values

If you meant AA5:AB15 instead of AA5:AA15, then

Sub Test()
Dim r As Range
For Each r In Range("C2",Cells(Rows.Count,"C").End(xlUp))
Range(Range("C1").Value & r.Value & ":" & Range("D1").Value & r(1,2).Value).ClearContents
Next r
End Sub

perfect. it worked like a charm
the two answers worked