This tip was posted on Lifehacker, a great source for all sorts of advice on technology and non-tech matters.  You may occasionally receive a PDF file that was inadvertently locked-down by its creator to the point that you cannot do what you need to with the file, such as print it.

When that happens, a free service called FreeMyPDF can be used to removed the inadvertent security restrictions and let you work with the file.   Just upload the file to this service and it will return the file to you with the security restrictions removed.  Please note that this service should not be used to gain access to a file you were not intended to work with.  Also, it will not remove security from a file that requires a password to view.  As the FreeMyPDF site warns, do not use this service for illegal purposes.