print .mbox file with html content

I have to print an email for the district office.
I use Evolution as Email program and I can save the emails in .mbox format. However when I save those email to a .mbox file and then do lp example.mbox it will print the email in an unreadable way.
It has html content, but I can't open the .mbox in Firefox. Is there a way I can convert .mbox to .pdf?
Or can I tell the printer how to treat that file somehow? I don't know how to render that html, it is correctly rendered in Evolution, but I can't print it from there because Evolution does not find my printers.