Any proggie to remove "hidden data" in a pdf ?

Hi,

I am looking for a program that can eradicate all personal data from a pdf
( such as name of author, company, program used to create pdf, etc)

Thes data are available to pdf reader software, under document properties,
and do not want it that way. MS Office has utilities to eradicate such
contents : anything thelike for pdf files ? I know pdf-analyzer pro can do
it, but it's not free ( and haven't found a way to use without $)

Any idea ???