Configuring git to for forget removed files

[Andrew Benton <b3nton@gmail.com>]

Hello world
I have a project that I store in a git repository. It's a bunch of source tarballs and
some bash scripts to compile it all. Git makes it easy to distribute any changes I make
across the computers I run. The problem I have is that over time the repository gets ever
larger. When I update to a newer version of something I git rm the old tarball but git
still keeps a copy and the folder grows ever larger. At the moment the only solution I
have is to periodically rm -rf .git and start again. This works but is less than ideal
because I lose all the history for my build scripts.
What I would like is to be able to tell git to not keep a copy of anything that has been
git rm. The build scripts never get removed, only altered so their history would be
preserved. Is it possible to make git delete its backup copies of removed files?

Andy