It's called cleancredits! I have not used it so I have no idea how it is to actually use. Looks like you'd have to clean out each subtitle by itself. Getting rid of a logo should be easier, though.

I got the zoom idea from a Guardian vid lola made before the logo and hardsub-free files were available. It wasn't noticeable at all when watched at the YouTube embed size; I didn't check fullscreen.