How to Remove Low CPC Bidders

1. Start compiling a list of advertisers on your website. Use tools like the Google AdSense Sandbox tool to preview what kind of ads are showing up on your site. Browse your site through various proxies to get a sense for what kinds of ads are showing up for different people. Record the advertiser's URLs in a spreadsheet.
2. Using spy tools like SpyFu, Compete or Keyword Spy, estimate the CPC your advertiser is paying per click. Unfortunately, in Google AdSense and in most online bidding platforms you can't actually see what each individual advertiser is paying. However, by using third-party spy tools you can get an idea of who's bidding low and who's bidding high. Keep in mind that most of this data is based on search pay-per-click (PPC) rather than contextual PPC, so the data will be skewed a little higher.

3. Identify your lowest paying advertisers and put their domains in a list. Make sure that if you remove these advertisers you'll still have enough high paying advertisers to continually display ads on your site. If you remove too many advertisers you might start displaying public service ads (PSA) that don't pay.
4. Using Google AdSense's 'allow and block' interface, block the advertisers that you've identified as low bidders.