[stutz]

I've been using Calibre to organize my library, and it's working quite well. However, I also sometimes use it to edit epubs, that I share with others. My problem is that it automatically embeds metadata into the file, which I have to manually remove before sending the epub to my recipient.
I don't mind it writing things like the author, the title, etc. but I don't want it to write my tags and custom columns, which are personal data and irrelevant outside my sorting system.
Is there a way to tell Calibre which columns to embed into the files, and which to keep private? I also would like it to not embed calibre-specific data, like the internal identifier, and the fact that it was edited by calibre.