Anyone know how to do this?

thanks,

My Thunderbird has a Star column which lets you do exactly that; mark selected messages with a star icon.

You could then use the QuickFilter to display only Starred messages and then do what you want with them.

You could also tag messages and use Quickfilter, or use a Saved Search to corral them into a separate virtual folder.

Both stars and tags can be applied automatically via a Message Filter.

Having separated out the wanted messages, you may need another addon, such as ImportExportTools to work with them in bulk. I must say that CSV isn't an obvious choice for email export, but IIRC that add-on supports it.

Thanks, but I'm having trouble finding the add-ons you mentioned that would allow export to .CSV file. I searched both ImportExportTools and IIRC and found neither. I could also use an excel file instead of CSV if that makes things easier.

Ha! IIRC = "If I Recall Correctly". It wasn't intended as an add-on suggestion.

https://addons.mozilla.org/en-US/thunderbird/addon/importexporttools/

You might be interested in the email address crawler add-on:

https://freeshell.de/~kaosmos/index-en.html#eac

but it posts to either a new message or to an address book. Neither is immediately suitable for export of email addresses. You could of course save to an address book and export this address book to CSV but it's not pretty nor elegant.

Zenos, thanks, you really helped me do this task.

Another idea:

Use addon extension 'Morefunctionsforaddressbook'

• https://freeshell.de/~kaosmos/morecols-en.html

Create a new address book for specific selected addresses/contacts. Select an email to see in Message Pane. In the header section, click on eg: From email address/contact select 'save recipient addresses' > 'as contacts(all)' pop up appears and you can choose that new address book. click on OK

Once you have collected the addresses, you can export that address book as a .csv file.