How to convert color pdf (ps) to b&w file

I have a pdf file, where foreground color is blue. It is very nice when you look at it at your monitor, but no so nice when you have to print it on b&w printer. Today I found the way how to convert a color pdf (or rather ps) into a b&w file. First you have to convert a pdf into a ps

pdf2ps file.ps

Printing into a file from Acrobat Reader doesn't work. Next you have to download this small perl script and use it

 bw_convert -b file.ps file-bw.ps

Now you have file ready to print on your b&w printer.
I found link to bw_convert script on this FAQu. There are more interesting advices.