Remove third party plugin from page

Good evening,

I want to remove the third party plugin that adds the opt in box to the top and bottom of my posts on a landing page I’m trying to create.

You can see an examples of the opt in form at http://www.nateanglin.com. I am creating my landing page through Premise and I have the option to add a custom CSS code to remve it, the problem is, I dont know what code to use.

Thanks in advance for your help.