To remove or delete spams from your blog, go to Comments section of the wordpress administration page. Delete all comments that you think a spam.

To protect your website against spam comments, i recommend you to install a spam protection plugin like akismet, anti-spam, or the likes.

I also recommend not to show submitted comments automatically as this will give idea to spammers that your website is not moderated.

Instead, go to Settings > Discussion and check the "Comment author must have a previously approved comment" checkbox under "Before a comment appears".