This page consists of screenshots from Security Settings – Block/Unblock IP Addresses Screen in Captcha Bank WordPress Plugin.
This gives an idea about how to Block/Unblock IP Addresses and the comments related to it. You can easily block an IP Address and choose Time Duration to block the IP for specific time period or to permanently block it from the site. You can also provide comments for blocking the IP Address.
Using this, you can view list of Blocked IP Addresses and if needed delete them from the list.