Bonjour à tous,
Un code (plutôt rapide si beaucoup de lignes) :
Sub Suppr()
Dim der&, t, i&, n&, j&
With Sheets("Sheet1")
der = .UsedRange.Row + .UsedRange.Rows.Count - 1
t = .Range("a2:c" & der)
For i = 1 To UBound(t)
If t(i, 1) <> "" And t(i, 3) <= 29 Then n = n + 1: For j = 1 To 3: t(n, j) = t(i, j): Next
Next i
.Range("a2:c" & der).ClearContents
If n > 0 Then .Range("a2:c2").Resize(n) = t
End With
End Sub