etiquette - Best way to politely remove someone from paper authorship who planned to contribute but did not?

(There is a similar question but not exactly.)

When you write a paper, you need various views. So you invite collaborators and it often works well. But assume that out of 5 invited, for example, one or two, don't contribute to the paper much but are kept on the email thread with updated versions of the manuscript.

How do you politely remove them from the author list (paper) and how do you say that politely in email. Do you just send them a separate email or a general "authorship rules" email to everybody?