My conversion from cvs to svn caused a bunch of files to end up with svn:keywords set for Author, Date, Revision, and Id. I recursively deleted the svn:keywords property from all the files with the following command. This could work with other svn property commands as well.
$ cd ~/sandbox/project/ ¬
$ find . ! -path "*svn*" \
> -exec svn propdel "svn:keywords" "{}" \; ¬