Sub DeleteComments()
Dim C As Comment, WS As Worksheet
Const TextToFind As String = ""
For Each WS In Worksheets
For Each C In WS.Comments
If UCase(C.Text) = UCase(TextToFind) Then C.Delete
Next
Next
End Sub
Here is the code to restrict the macro to only one sheet (assumed to be "Sheet1" for the code... change it as appropriate for your actual setup)...Only one sheet has comments. However, the Workbook is big so it is best to limit the search to one sheet.
Sub DeleteComments()
Dim C As Comment
Const TextToFind As String = ""
For Each C In Worksheets("Sheet1").Comments
If C.Text = TextToFind Then C.Delete
Next
End Sub