Algo rápido y eficaz
Public Sub DeleteString(ByRef Str As String, ByRef Begin As String, ByRef EndS As String)
Dim P As Long
Dim P2 As Long
P = InStr(1, Str, Begin)
P2 = InStr(P, Str, EndS)
If (Not (CBool(P)) Or Not (CBool(P2))) Then
Exit Sub
End If
Str = Mid(Str, 1, P - 1) & Mid(Str, P2 + Len(EndS), Len(Str))
End Sub
Uso:
Dim A As String
A = "Este es un 345 aaa 661 ejemplo"
MsgBox A
DeleteString A, "45", "66"
MsgBox A