How to Fight Spammers - Annoying Hardly Unreadable Captcha in Facebook

I put my own website http://media-islam.or.id on my own wall, yet I have to fill a very hard to read Captcha. It's annoying. Actually when "Not Spam">"Spam", FB should remove the URL from black/grey list. Or FB should use a simple math yet easy to read such as 3+4=? where people should enter the right answer such as 7.