Comment on How to delete million of files on busy Linux servers (Work out Argument list too long) by frog.
a even better way is: write a tool in c to remove the files, you can hard-encode the direcory path in the code, and sleep periodically, to avoid stressing the server.
frog Also Commented
How to delete million of files on busy Linux servers (Work out Argument list too long)
you might want to try moving all the non-related files outside the directory, and give it one shot: rm -rf DIR