Hi everyone, I just want to share with you this useful tool to crop pdf, it's quite good as it shows all the pages overlapping, so that the user can decide how to crop the document without cutting content, also it allows to crop chosen pages differently if needed.
http://briss.sourceforge.net/
it requires a little bit time to get use to it, but the result are great. I hope I didn't post something that is already posted before.