wanna delete refs and free space. How?

$ rm -rf .git test00.txt                                                                                               [2/69]
$ dd if=/dev/random bs=1m count=1 >> test00.txt                                                                              
1+0 records in
1+0 records out
1048576 bytes transferred in 0.070135 secs (14950799 bytes/sec)
$ ls -l
total 1032
-rw-r--r--  1 meme  wheel  1048576 13 ноя 18:38 test00.txt
$ git init
Initialized empty Git repository in /tmp/test00/.git/
$ git add test00.txt                                                                                                         
$ git add test00.txt ^C                                                                                                      
$ ^C
$ ^C
$ git commit -a -m init                                                                                                      
[master (root-commit) 95c3722] init
 1 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 test00.txt
$ dd if=/dev/random bs=1m count=1 >> test00.txt                                                                              
1+0 records in
1+0 records out
1048576 bytes transferred in 0.082013 secs (12785465 bytes/sec)
$ ls -l
total 2056
-rw-r--r--  1 meme  wheel  2097152 13 ноя 18:39 test00.txt
$ git commit -a -m 'commit 00'                                                                                               
[master 787c97c] commit 00
 1 files changed, 0 insertions(+), 0 deletions(-)
$ dd if=/dev/random bs=1m count=1 >> test00.txt                                                                              
1+0 records in
1+0 records out
1048576 bytes transferred in 0.244536 secs (4288024 bytes/sec)
$ git commit -a -m 'commit 01'                                                                                               
[master 60870d3] commit 01
 1 files changed, 0 insertions(+), 0 deletions(-)
$ du -s .git
6248    .git
$ git log
commit 60870d30231f63a12f0eac1bc34157cb50549899
Author: Peter Vereshagin <peter@vereshagin.org>
Date:   Sun Nov 13 18:39:47 2011 +0400

    commit 01

commit 787c97cd5771ec93ae3f91e4ff07ec983c0a16c6
Author: Peter Vereshagin <peter@vereshagin.org>
Date:   Sun Nov 13 18:39:37 2011 +0400

    commit 00

commit 95c37221aeb05ac11ec41857784b98c0a499a53f
Author: Peter Vereshagin <peter@vereshagin.org>
Date:   Sun Nov 13 18:39:04 2011 +0400

    init