首先，您应该始终在模块顶部使用Option Explicit，以便强制您正确声明所有变量。
无需遍历整个列。仅循环通过实际具有值的单元格。为此，我们可以使用Worksheet.UsedRange 属性并使用所需范围执行Intersect。
由于您只对文本感兴趣，因此代码应该能够忽略错误和数字。
此外，无需多次读取单元格值，因此最好使用数组仅读取一次。 With 构造有助于轻松读取单元格字体颜色。
这是我想出的 - 保留原始方法名称：
Option Explicit
Public Sub DeleteComments(ByVal rng As Range)
Dim tempRng As Range
Dim tempArea As Range
Set tempRng = GetUsedRange(rng)
If tempRng Is Nothing Then Exit Sub
'Store app state and turn off some features
Dim scrUpdate As Boolean: scrUpdate = Application.ScreenUpdating
Dim calcMode As XlCalculation: calcMode = Application.Calculation
Dim evEnabled As Boolean: evEnabled = Application.EnableEvents
With Application
If .ScreenUpdating Then .ScreenUpdating = False
If calcMode <> xlCalculationManual Then .Calculation = xlCalculationManual
If .EnableEvents Then .EnableEvents = False
End With
'Loop through all areas. Check/update only relevant values
For Each tempArea In tempRng.Areas
If tempArea.Count = 1 Then
UpdateCell tempArea, tempArea.Value2
Else
Dim arr() As Variant: arr = tempArea.Value2 'Read whole range into array
Dim rowsCount As Long: rowsCount = tempArea.Rows.Count
Dim i As Long: i = 1
Dim j As Long: j = 1
Dim v As Variant
'For Each... loop is faster than using 2 For... Next loops on a 2D array
For Each v In arr 'Column-major order
If VarType(v) = vbString Then 'Only check strings - ignore numbers and errors
If Len(v) > 0 Then UpdateCell tempArea.Cells(i, j), v
End If
i = i + 1
If i > rowsCount Then 'Switch to the next column
j = j + 1
i = 1
End If
Next v
End If
Next tempArea
'Restore app state
With Application
If scrUpdate Then .ScreenUpdating = True
If calcMode <> xlCalculationManual Then .Calculation = calcMode
If evEnabled Then .EnableEvents = True
End With
End Sub
Private Function GetUsedRange(ByVal rng As Range) As Range
If rng Is Nothing Then Exit Function
On Error Resume Next
Set GetUsedRange = Intersect(rng, rng.Worksheet.UsedRange)
On Error GoTo 0
End Function
Private Function UpdateCell(ByVal cell As Range, ByVal value As Variant)
Dim textOut As String
Dim charExcluded As Boolean
Dim i As Long
For i = 1 To Len(value)
With cell.Characters(i, 1).Font
If (.ColorIndex = 1 Or .ColorIndex = -4105) And Not .Strikethrough Then
textOut = textOut & Mid$(value, i, 1)
Else
charExcluded = True
End If
End With
Next i
If charExcluded Then cell.Value2 = textOut
If IsNull(cell.Font.ColorIndex) Then
cell.Font.ColorIndex = 1
ElseIf cell.Font.ColorIndex <> 1 Then
cell.Font.ColorIndex = 1
End If
End Function
如您所见，我将代码拆分为几个辅助函数，以便于维护。
要使用它，只需在所需范围内调用它。例如：
DeleteComments Selection 'if you already have a selected range
'Or
DeleteComments Range("M:M") 'as in your original post
另一个好处是，无论您想要的范围是一列、一行、多列/行还是多区域范围，此代码都可以正常工作。为您提供很大的灵活性，并尽可能快地完成。
编辑#1
如果我们只检查混合颜色的单元格，UpdateCell 函数可能会更快：
Private Function UpdateCell(ByVal cell As Range, ByVal value As Variant)
Dim textOut As String
Dim charExcluded As Boolean
Dim i As Long
If IsNull(cell.Font.ColorIndex) Then
For i = 1 To Len(value)
With cell.Characters(i, 1).Font
If (.ColorIndex = 1 Or .ColorIndex = -4105) And Not .Strikethrough Then
textOut = textOut & Mid$(value, i, 1)
Else
charExcluded = True
End If
End With
Next i
If charExcluded Then cell.Value2 = textOut
cell.Font.ColorIndex = 1
ElseIf cell.Font.ColorIndex <> 1 Then
cell.Value2 = Empty
cell.Font.ColorIndex = 1
End If
End Function