[gol8erl8]

I'd like to clear the metadata from many ebooks (.EPUB) except for certain fields, namely title, author, and possibly the identifier and source that corresponds to the Project Gutenberg book number. I am currently using Edit metadata in bulk to do this, i.e.

Spoiler:

Rating : Not rated : Apply rating
Publisher : (Blank) : Clear pub
Remove tags : (Blank) : Remove all
Series : (Blank) : Clear series
Date : Undefined : Apply date (Clicked remove button)
Published : Undefined : Apply date (Clicked remove button)
Languages : (Blank) : Remove all
Change cover : Remove cover
Set the comments for all selected books : (Blank)

However, when I use Edit book, I still find unwanted bits in the content.opf file between the <metadata> tags, including <dc:rights> and <dc:date opf:event="conversion">. Moreover, when I convert from .EPUB to .AZW3, I lose the <dc:identifier opf:scheme="URI" id="id"> and <dc:source> tags, which may not be desirable should I decide to keep/modify these. Here is an example of metadata from A Tale of Two Cities by Charles Dickens found at https://www.gutenberg.org/ebooks/98.epub.images :

Original

Spoiler:

<metadata>
    <dc:title>A Tale of Two Cities</dc:title>
    <dc:creator opf:role="aut" opf:file-as="Dickens, Charles">Charles Dickens</dc:creator>
    <dc:rights>Public domain in the USA.</dc:rights>
    <dc:identifier opf:scheme="URI" id="id">http://www.gutenberg.org/98</dc:identifier>
    <dc:date>1994-01-01T05:00:00+00:00</dc:date>
    <dc:date opf:event="conversion">2020-03-01T08:37:22.360047+00:00</dc:date>
    <dc:source>https://www.gutenberg.org/files/98/98-h/98-h.htm</dc:source>
    <dc:subject>Historical fiction</dc:subject>
    <dc:subject>France -- History -- Revolution</dc:subject>
    <dc:subject>1789-1799 -- Fiction</dc:subject>
    <dc:subject>London (England) -- History -- 18th century -- Fiction</dc:subject>
    <dc:subject>War stories</dc:subject>
    <dc:subject>Executions and executioners -- Fiction</dc:subject>
    <dc:subject>French -- England -- London -- Fiction</dc:subject>
    <dc:subject>Lookalikes -- Fiction</dc:subject>
    <dc:subject>British -- France -- Paris -- Fiction</dc:subject>
    <dc:subject>Paris (France) -- History -- 1789-1799 -- Fiction</dc:subject>
    <dc:language>en</dc:language>
    <dc:identifier opf:scheme="calibre">7c7b2a30-5b0b-41e9-a1fa-b1109aa06373</dc:identifier>
    <meta name="cover" content="item33"/>
    <meta name="calibre:title_sort" content="Tale of Two Cities, A"/>
    <meta name="calibre:author_link_map" content="{&quot;Charles Dickens&quot;: &quot;&quot;}"/>
  </metadata>

After Edit metadata in bulk

Spoiler:

<metadata>
    <dc:title>A Tale of Two Cities</dc:title>
    <dc:creator opf:role="aut" opf:file-as="Dickens, Charles">Charles Dickens</dc:creator>
    <dc:rights>Public domain in the USA.</dc:rights>
    <dc:identifier opf:scheme="URI" id="id">http://www.gutenberg.org/98</dc:identifier>
    <dc:date>0101-01-01T00:00:00+00:00</dc:date>
    <dc:date opf:event="conversion">2020-03-01T08:37:22.360047+00:00</dc:date>
    <dc:source>https://www.gutenberg.org/files/98/98-h/98-h.htm</dc:source>
    <dc:identifier opf:scheme="calibre">7c7b2a30-5b0b-41e9-a1fa-b1109aa06373</dc:identifier>
    <meta name="cover" content="item33"/>
    <meta name="calibre:title_sort" content="Tale of Two Cities, A"/>
    <meta name="calibre:author_link_map" content="{&quot;Charles Dickens&quot;: &quot;&quot;}"/>
  </metadata>

Subsequently using Polish books and Convert books (from .EPUB to .AZW3)

Spoiler:

<metadata xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:calibre="http://calibre.kovidgoyal.net/2009/metadata" xmlns:opf="http://www.idpf.org/2007/opf">
    <dc:title>A Tale of Two Cities</dc:title>
    <dc:creator opf:role="aut" opf:file-as="Unknown">Charles Dickens</dc:creator>
    <dc:contributor opf:role="bkp" opf:file-as="calibre">calibre (4.10.1) [https://calibre-ebook.com]</dc:contributor>
    <dc:identifier id="calibre_id" opf:scheme="calibre">7c7b2a30-5b0b-41e9-a1fa-b1109aa06373</dc:identifier>
    <dc:date>0100-12-31T19:00:00-05:00</dc:date>
    <dc:language>eng</dc:language>
    <dc:identifier opf:scheme="MOBI-ASIN">7c7b2a30-5b0b-41e9-a1fa-b1109aa06373</dc:identifier>
    <dc:rights>Public domain in the USA.</dc:rights>
  </metadata>

Is there a more thorough way of clearing metadata that is faster than individually opening and modifying the metadata in Edit books?