How to delete all alphabetic index entries at once

In writer I have a large document that I created an alphabetic index for. I have chosen to delete the index as I want to create another one. However, deleting the index does not remove all the index entry fields within the document. Is there any way to do this automatically without manually going through the whole document?

Have a look to the explanation from @Regina

Thanks for the answer. But I am looking for an automatic solution. The document is too large to go through and delete everything manually that way.