I would add a header row, then do data|filter|autofilter on that column.

Use the dropdown arrow
Contains
beta

And then delete the visible rows

Then remove the autofilter.

Sub DeleteBeta()
   Dim rng As Range, cell As Range, rngToDelete As Range
   Set rng = Intersect(Range("A:A"), ActiveSheet.UsedRange)
   For Each cell In rng.Cells
       If UCase(cell.Value) Like "*BETA*" Then
           If rngToDelete Is Nothing Then
               Set rngToDelete = cell
           Else
               Set rngToDelete = Union(rngToDelete, cell)
           End If
       End If
   Next
   If Not rngToDelete Is Nothing Then
       rngToDelete.EntireRow.Delete
   End If
End Sub