Here is a macro that you can try...
Code:
Sub ReduceToNumbersOnly()
  Dim X As Long, Z As Long, LastRow As Long, Strng As String, vArr As Variant
  Const FirstOutputCell As String = "B2"
  Const DataColumn As String = "A"
  Const StartRow As Long = 2
  LastRow = Cells(Rows.Count, DataColumn).End(xlUp).Row
  vArr = Cells(StartRow, DataColumn).Resize(LastRow - StartRow + 1)
  For X = 1 To UBound(vArr)
    Strng = ""
    For Z = 1 To Len(vArr(X, 1))
      If Mid(vArr(X, 1), Z, 1) Like "#" Then Strng = Strng & Mid(vArr(X, 1), Z, 1)
    Next
    vArr(X, 1) = Strng
  Next
  Range(FirstOutputCell).Resize(UBound(vArr)) = vArr
End Sub
The only thing you need to do is change the three constants (the Const statements) to match your actual layout. You can set the FirstOutputCell constant to your first data cell if you want to overwrite your original data with the numbers contained within them.