Removing google public service ads on adsense

You usually get this when you first added your adsense codes to your site. Its alright to get this during this time as adsense wasn't able to get a cache of your keywords yet. It may take some time to get revenue generating ads on your site specially if your content has less meaningful keywords in it. According to the google help center, it would take approximately 48 hours to remove the Gulf Hurricane Relief ad on your site. If its been there for weeks then your copy might have some problems in it.

Editing robots.txt
There are several ways to remove the PSA from appearing on your site, but the most efficient way is to change your content. First things first, your robots.txt might have been configured to disallow adsense crawlers from visiting your site. If you are able to edit your robots.txt file, you may add the following code below:

User-agent: Mediapartners-Google*
Disallow:

Avoid iFrames or Frames
If you have placed your adsense code in an iFrame then the crawler will have no way of getting relevant keywords thus displaying in the Public  Service  Ads. Google crawlers will have a hard time figuring out which content to get for the ads inside frames so its best not to place your ads in a separate frame or simply avoid using frames on your site just to be safe.

Choose  your content wisely
Content is the most important factor in determining the adsense ads that is displayed on your website. the more content you the greater chances of getting a relevant ad. Make sure you have enough content for the crawler to read. Also, the google crawler can't read images, audio files, flash content, java applets or anything except plain text. If you have a small amount of content and you have set your ads to display only images then this might be the reason for displaying only PSA ads. Try changing your adsense codes to display text and images ads.

Negative Keywords
Avoid negative keywords, this includes anything that is related to d%ath, sickness, p%rnography, dr%gs, etc. At anytime avoid mentioning these words on all of your content, but opps there you go i have just listed them here anyway.

Avoid automatic refresh
If yous page contains the HTML auto refresh code, it might also be the reason why your site is displaying public service ads. Remove the meta refresh code from your page and observe if the PSA ads have been removed. The meta refresh code looks like this one below, remove them:



Adsense ad in a login page
Placing ads on a page that requires user access does not allow the google crawler to visit the page to get the relevant keywords therefore displaying public service ads instead. Avoid placing adsense code behind a login page.

Avoid Session Ids on URLs
Adsense also relies heavily on the URL to display relevant ads. Having a session id on the url confuses the crawler to ad a relevant keyword because your URL keeps on changing. You may use the input type hidden HTML attribute instead of placing the session id in the urls

Unsupported localization
If you site is displaying other language aside from English then this might be the reason why its displaying public service ads. Here's a list of country currently supported by adsense.
Arabic 
Bulgarian
Chinese (simplified)
Chinese (traditional)
Croatian
Czech
Danish
Dutch
English
Finnish
French
German
Greek
Hebrew
Hungarian
Italian
Japanese
Korean
Norwegian
Polish
Portuguese
Romanian
Russian
Serbian
Slovak
Spanish
Swedish
Turkish