re-generate the PDF with standard non-embedded fonts

i got thousands of pdf files ,many of them have a few embedding fonts,can i transform orginal pdf to a new one ,all the texts or characters are using one of the 5 standard font families(Times,  Helvetica, Courier, Symbol and ZapfDingbats.)

can gs do this kind of thing?how ??


from http://www.aivosto.com/vbtips/pdf-optimize.html


"PDF comes with 5 standard font families. The families are Times,  Helvetica, Courier, Symbol and ZapfDingbats. All PDF readers support  these standard fonts.
 
For all other fonts, PDF writers normally embed the font  data in the PDF file. Embedding means copying. The file includes a copy  of the entire font, or a part of it. When a Garamond font is used, for  example, the font glyphs get copied in the PDF. This consumes a lot of  space."