How to Block Specific ad from Adsense ? Lafandar

As Being Adsense user from last 4 month I often saw same ad running on 3 different slots.I don't even know what is the reason behind that but when I come to know these were the ads from the advertisers who pays less.So how to block such advertisers lets know

You can prevent ads from specific advertiser URLs from showing on your site within the Allow & block ads tab. The maximum number of advertiser URLs you can block is 500 per AdSense product. You can apply your 500 blocks at the site level or at the product level and in any combination you like up to the limit. Let's say you run four sites and you block 100 advertiser URLs on each of those sites. If you then block another 100 advertiser URLs across all of your sites, you'll have reached your 500 URL limit.
You can block an advertisement in two ways :-

At Website Level

1.Sign in to your AdSense account.

2.Visit the Allow & block ads tab.

3.In the sidebar, click Content.

4.Under Content, select the domain or subdomain that you want to set the block on.

5.In the horizontal bar across the top of the page, click the Advertiser URLs tab.

6.Enter URLs in the box provided, then click Block URLs. Ads from blocked URLs should stop showing on your pages within 24 hours

Block at the product level

1.Sign in to your AdSense account.

2.Go to the Allow & block ads tab.

3.In the sidebar, select your product. For example, select “Content” for AdSense for content.

4.In the horizontal bar across the top of the page, click the Advertiser URLs tab.

5.Enter URLs in the box provided, then click Block URLs. Ads from blocked URLs should stop showing on your pages within 24 hours.

Thats all.Have any questions ask in comments below.