Removing Documents Archive.org and alexa.com From the Wayback Machine

The Internet Archive is not interested in offering access to web sites or other Internet documents whose authors do not want their materials in the collection. To remove your site from the Wayback Machine, place a robots.txt file at the top level of your site (e.g. www.yourdomain.com/robots.txt).

The robots.txt file will do two things:

It will remove documents from your domain from the Wayback Machine.

It will tell us not to crawl your site in the future.

To exclude the Internet Archive’s crawler (and remove documents from the Wayback Machine) while allowing all other robots to crawl your site, your robots.txt file should say:

User-agent: ia_archiver

Disallow: /

Robots.txt can be used to block access to the whole domain, or any file or directory within.

Fonte: arquive.org