Not exactly sure but try: 
Sub test()

Dim l As Long
Dim m As Long
Dim lRow As Long
Dim i As Integer
Dim j As Integer
Dim x As Double
Dim y As Double

Application.Calculation = xlCalculationManual
Application.ScreenUpdating = False

lRow = Range("AL66536").End(xlUp).Row

Range("AL:AV").Copy
Range("AL:AV").PasteSpecial xlPasteValues
Application.CutCopyMode = False
Range("AL1").Select

For i = 38 To 48
    For l = 1 To lRow
        Cells(l, i).Select
        If Cells(l, i).Value <> "" Then
        x = Round(Cells(l, i).Value, 3)
            For j = 38 To 48
                For m = ActiveCell.Row + 1 To lRow
                    If IsNumeric(Cells(m, j).Value) = True Then
                        y = Round(Cells(m, j).Value, 3)
                    End If
                    If y = x Then
                        Selection.Offset(1, 0).Select
                        Selection.Resize(10, 1).Select
                        Selection.ClearContents
                    End If
                Next m
            Next j
        End If
    Next l
Next i

Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True

End Sub