I had some real trouble with one text I had added to each page. I got the text off now, but not from quite the place I would have expected. I used WordPress editor to go to the header.php file. In this file I edited some text that was before <body> tags and I happened to successfully remove that text. The only reason that I even touched the part outside the body tags, was because I was quite desperate about this.
The line I commented out was just wp_head(); inside php tags. This does seem quite harmless, but it added a big minus to my sites overall look.
I hope that someone with a similar trouble can find this. I still would encourage people to randomly modify some header files in their WordPress pages, that would just add some fun to writing contents. At least it does for me.