VBA Remove Duplicate Values From Multiple Columns

You could simply amend your original code to something like this:

Sub RemoveDuplicateCells(ws As Worksheet)
    
    Dim i As Long
    Dim LR As Long
    Dim vColumns As Variant
    Dim vCol As Variant
    
    vColumns = Array("B", "C", "D", "F")
    
    Application.ScreenUpdating = False
    
    With ws
        LR = ws.Range("C" & Rows.Count).End(xlUp).Row
        For i = LR To 8 Step -1
            For Each vCol In vColumns
            With ws.Range(vCol & i)
                If WorksheetFunction.CountIf(ws.Columns(vCol), .Value) > 1 Then .ClearContents
            End With
            Next vCol
        Next i
    End With
End Sub