Using Public Domain Certification
Creative Commons has a worksheet on their site for Public domain tools. After you indicate you do want to certify material as in the public domain, Creative Commons takes you to a new page for Public Domain Certification. Creative Commons has quite a bit of information for you to read before you are at the point where you are certifying a work as in the public domain. They also allow you to opt out of the process. If you follow through, they give you a section of HTML for the web page where what you are certifying resides. The HTML code means that search engines crawling the site find that page and can read the work is in the public domain, if some one is searching for public domain materials.
They also have a place to get text, if you are certifying something not on the Internet.
The text tells you the work in question is under the Creative Commons Public Domain certification. Then they give a URL for the Public Domain certification information: http://creativecommons.org/licenses/publicdomain/ , or tell you to "send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA." *
* This text on this page is here for example purposes only, and does not indicate that this specific web page is in the public domain.