Safe Way to Preview Adsense ads

I received a question from a new Adsense blogger asking if they would breach Google's terms of service by viewing their own Adsense pages. Of course you need to check the Adsense ad layout on your pages from time to time, although you need to take care - NEVER click on your own Adsense Ads. By viewing your pages using Internet Explorer you can also install the Google AdSense Preview Tool. This is an addition to the right-click menu for Windows Internet Explorer 6.x, allowing you to preview the ads that may show on any web page. I find this has limited use, but it can help you find the URLs of Made For Adsense sites that you can list in your competitive ad filter. The preview tool is not yet available for Firefox, sadly.