Removing "other" stuff from custom post type

I created a custom post type. Pretty cool stuff.

The issue I have is I cannot remove “other” plugin meta boxes from the edit page. Specifically, there is a checkbox that Kontera adds to the edit page, and Zemanta adds their meta-box as well.

I tried removing “everything” (according to the documentation I read) and then adding the meta boxes I want back in, but the “other” stuff remains.

Kontera is inside a div with an id of “postbox-container-1” with a class of “postbox-container”. The actual Kontera div is just set up with a class of “postbox”. Is there anyway to remove this?

Zemanta shows up in the same sidebar, inside a div with a class of “zemanta-wrap postbox”.

I realize I could just hide the Kontera box using CSS, but Zemanta slows down the browser when it tries to load, and I would just as soon eliminate it from the editor for the custom post type completely.