Triggering post build and passing in branch name from successful build

Triggering post build and passing in branch name from successful build

I've used Google and looked at the Docs but can't find an answer.
I want to trigger another build or a rake script to do some cleaning up of
files after a successful build. I currently use Rake to do my build and
pass in %teamcity.build.branch% to it.
I would like to know if I can pass the same branch name of the successful
build to the triggered build or script. I can then use this to do some
tidying up.
Thanks