Option Explicit
'
Sub NettoyerFeuilles()
Dim Feui As Worksheet, LMax As Long, CMax As Long
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
For Each Feui In ActiveWorkbook.Worksheets
On Error Resume Next
LMax = Feui.UsedRange.Find("*", After:=Feui.[A1], LookIn:=xlFormulas, Lookat:=xlWhole, _
SearchDirection:=xlPrevious, SearchOrder:=xlByRows).Row
If Err Then LMax = 0: Err.Clear
CMax = Feui.UsedRange.Find("*", After:=Feui.[A1], LookIn:=xlFormulas, Lookat:=xlWhole, _
SearchDirection:=xlPrevious, SearchOrder:=xlByColumns).Column
If Err Then CMax = 0
On Error GoTo 0
If LMax < 25 Then LMax = 25
If CMax < 26 Then CMax = 26
Feui.Rows(LMax + 1).Resize(Feui.Rows.Count - LMax).EntireRow.Delete
Feui.Columns(CMax + 1).Resize(Feui.Columns.Count - CMax).EntireColumn.Delete
Next Feui
Application.Calculation = xlCalculationAutomatic
End Sub