Cropping PDFs

I am looking for a way to truly crop a PDF document so that the cropped area is completely removed, and not just hidden. So far I have not found a tool to do this, and the only workaround I've found is to "refry" the PDF after cropping.

For most PDFs this works ok, but for scanned PDFs not so good. No matter what settings I use, the resulting "refried" PDF ends up with reduced resolution and a much larger file. I turned off all of the downsampling and compression, and maximized the resolution (all of which undoubtedly increased the file size), but the result was still worse (and a much larger file) than the original scanned document.

I ended up cropping the image in Photoshop, which is hardly an acceptable solution.

Does anyone know of a better way to do this?

TIA