How do you...

Hi folks,

I was hoping anyone could enlightne me as to how to achive the effect shown in these examples below.

Section of image in header of template, lime green area
http://www.templatehelp.com/aff/preview.php?aff=Hypergurl_Templates&skin=24&locale=en¤cy=0&pr=yes&src=yes&nt=yes&help=yes&sample=yes&faq=yes&nmg=yes&auth=yes&down=yes&chm=&hide_flash=0&search=&PHPSESSID=054158a5c4308487f62464a6401fbc3f&referer=http%3A%2F%2Fwww.hypergurl.com%2Fwebtemplatestore.html&i=10523

How do they make those ragged edges?

Another example here:
http://www.templatehelp.com/aff/preview.php?aff=hulk&skin=21&locale=en¤cy=0&pr=yes&src=yes&nt=yes&help=yes&sample=yes&faq=yes&nmg=yes&auth=yes&down=yes&chm=&hide_flash=0&search=&PHPSESSID=054158a5c4308487f62464a6401fbc3f&referer=http%3A%2F%2Fwww.steves-templates.com%2Ffashion-templates.html&i=8817

Any help would be greatly appreciated.

search for photoshop + grunge brushes on google.