PDF Eraser can help you modify the contents of PDF documents, mostly by erasing unwanted elements. Likewise, it can also remove complete pages that are no longer necessary. Fortunately, not only deleting contents is supported as the tool also lets you add text and pictures to the original file. Moreover, the application can be used to rotate pages to the right orientation.
The application has a nice easy-to-use interface. However, the Page Cutter window cannot be resized, which forces the user to work with small page thumbnails. Also, I don’t see why the program necessarily requires to load a document when you open the Page Cutter. I think it should let you work with the currently opened PDF instead.
Modifying the contents of a document is as easy as drawing in Paint. You can use erasers of various sizes and drag them over the area to delete. Similarly, it lets you add text and images. It is a pity, though, that the images cannot be resized. Unfortunately, it does not allow selecting and deleting a rectangular area either. Finally, after making the desired changes, you can save the document to a new file.
All in all, PDF Eraser is probably the easiest way to delete undesired objects from a PDF file. However, this certainly has inconveniences, too. And not allowing to work with objects and layers may be the worst.