diff --git a/deserialize.py b/deserialize.py
index fe0cb09..a67645b 100644
--- a/deserialize.py
+++ b/deserialize.py
@@ -75,6 +75,7 @@ def deserialize_TxOut(d, owner_keys=None):
 
 def parse_Transaction(vds):
   d = {}
+  start = vds.read_cursor  # XXX breaks BCDataStream abstraction, do we care?
   d['version'] = vds.read_int32()
   n_vin = vds.read_compact_size()
   d['txIn'] = []
@@ -85,6 +86,7 @@ def parse_Transaction(vds):
   for i in xrange(n_vout):
     d['txOut'].append(parse_TxOut(vds))
   d['lockTime'] = vds.read_uint32()
+  d['tx'] = vds.input[start:vds.read_cursor]
   return d
 def deserialize_Transaction(d, transaction_index=None, owner_keys=None):
   result = "%d tx in, %d out\n"%(len(d['txIn']), len(d['txOut']))
diff --git a/freeable.py b/freeable.py
new file mode 100755
index 0000000..c79f458
--- /dev/null
+++ b/freeable.py
@@ -0,0 +1,87 @@
+#!/usr/bin/env python
+#
+# Read the block database, find out how many transactions
+# could be purged and how many bytes they take up.
+# TODO: find out how many Merkle hashes could be purged.
+#
+from bsddb.db import *
+import logging
+import os
+import sys
+
+from BCDataStream import *
+from block import scan_blocks
+from deserialize import parse_Block
+from util import determine_db_dir, create_env
+import Crypto.Hash.SHA256 as SHA256
+
+import binascii  # debugging
+
+def main():
+  import optparse
+  parser = optparse.OptionParser(usage="%prog [options]")
+  parser.add_option("--datadir", dest="datadir", default=None,
+                    help="Look for files here (defaults to bitcoin default)")
+  (options, args) = parser.parse_args()
+
+  if options.datadir is None:
+    db_dir = determine_db_dir()
+  else:
+    db_dir = options.datadir
+
+  try:
+    db_env = create_env(db_dir)
+  except DBNoSuchFileError:
+    logging.error("Couldn't open " + db_dir)
+    sys.exit(1)
+
+  blockfile = open(os.path.join(db_dir, "blk%04d.dat"%(1,)), "rb")
+  block_datastream = BCDataStream()
+  block_datastream.map_file(blockfile, 0)
+
+  blocks = []
+  def gather_stats(block_data):
+    block_datastream.seek_file(block_data['nBlockPos'])
+    blocks.append(parse_Block(block_datastream))
+    return True
+
+  scan_blocks(db_dir, db_env, gather_stats)
+  blocks.reverse()
+  print 'loaded ', len(blocks), ' blocks'
+
+  tx = {}
+  total_tx = 0
+  freeable_tx = 0
+  total_bytes = 0
+  freeable_bytes = 0
+
+  for data in blocks:
+    coinbase = True
+    for txn in data['transactions']:
+      tx_hash = SHA256.new(SHA256.new(txn['tx']).digest()).digest()
+      #print '> ', binascii.hexlify(tx_hash)
+      tx_bytes = len(txn['tx'])
+      tx[tx_hash] = (tx_bytes, len(txn['txOut']))
+      total_tx += 1
+      total_bytes += tx_bytes
+
+      if coinbase:
+        coinbase = False
+      else:
+        for txin in txn['txIn']:
+          #print '< ', binascii.hexlify(txin['prevout_hash'])
+          (bytes, live) = tx[txin['prevout_hash']]
+          if live == 1:
+            freeable_bytes += bytes
+            freeable_tx += 1
+            del tx[txin['prevout_hash']]
+          else:
+            tx[txin['prevout_hash']] = (bytes, live - 1)
+
+  db_env.close()
+
+  print freeable_tx, 'of', total_tx, 'tx freeable'
+  print freeable_bytes, 'of', total_bytes, 'tx bytes freeable'
+
+if __name__ == '__main__':
+    main()

#! /bin/sh

# This script writes a file named recovered_wallet.dat.
# Make plenty of backups when manipulating wallet files.
# This software is offered freely without warranty of any kind.

# These instructions are for people who have a corrupt copy of a
# wallet.dat file with a nonempty balance and no other means to
# recover the coins.  The wallet.dat format currently (Original
# Bitcoin Client 0.3.x) is a Berkeley DB file.  You should search for
# and try the usual Berkeley DB recovery mechanisms before you attempt
# this method.

# Replace the values of PUBKEYHEX and KEYPAIRHEX below with a
# hex-encoded public key and full key pair, respectively, from your
# corrupt wallet.dat.  In a hex dump, the public key is 65 bytes
# following a sequence "03 6b 65 79 41".  The keypair consists of
# another copy of the public key (somewhere else in the file) preceded
# by 217 bytes, which presumably encode the private key.  The 217
# bytes always seem to begin with 0xfd (253).  These observations are
# a result of reverse-engineering the file format and may not always
# apply.  If you can confirm or correct this, please post!

# The following short Perl script may find the values in a file called
# CORRUPT_wallet.dat:

# #!/usr/bin/perl
# $_ = `cat CORRUPT_wallet.dat`;
# while (/keyA(.{65})/sg) { $k{$1}++ }
# for my $k (keys(%k)) {
#     while (/(\xfd.{216}\Q$k\E)/sg) {
#         print("PUBKEYHEX=", unpack("H*", $k), "\n");
#         print("KEYPAIRHEX=", unpack("H*", $1), "\n\n");
#     }
# }

# A typical wallet.dat contains 100 or more of these key pairs, which
# you would try one by one if you don't know which one contains your
# coins.  http://blockexplorer.com/q contains tools to convert from a
# public key to an address, and you can look up each address (with
# http://blockexplorer.com) to see if it has a balance.

# To convert the example public key below to an address:
# http://blockexplorer.com/q/hashpubkey/04ff5443fcd00b8f3844569dcaa42662d90e0c8afb1fe35804c320e5bb08ea6dadc3231767aa13b9dd6abcb45a8cd0497490d5c2a78ff85ea61711394b3b08e5c9
# returns the "hash" 37A85118AD7DBE78132CF13DCD90F35D701172C5, which,
# if given as the last component of
# http://blockexplorer.com/q/hashtoaddress/37A85118AD7DBE78132CF13DCD90F35D701172C5
# yields the address 165HoQXzxc26xxkECD95icTAscZW8TngFU.
# (In the testnet, this is mkbF6TcymdTMk5Dqun7TYXfVjcAD2g5cSj.)
# The bitcointools package contains Python code for doing the same.

# If this script succeeds for a given address, exit any running
# bitcoin process.  Back up any existing wallet.dat and install
# the new file (recovered_wallet.dat) as wallet.dat.  Run "bitcoind
# -rescan".  (Maybe the GUI will work, but I've tested only the
# daemon.)  After the program updates and scans the block chain,
# "bitcoind getblockcount" will show the current block count as shown
# by http://blockexplorer.com.  "bitcoind listaccounts" should show
# one account with an empty name and the coin's value, for example:

# {
#     "" : 123.456
# }

# Get a known good address and send the full balance to it using
# "bitcoind sendtoaddress {KNOWN_GOOD_ADDRESS} {BALANCE}".  If you
# send less than the full balance, the remainder will go to a change
# address in the recovered wallet, complicating matters.

# "bitcoind sendtoaddress ..." outputs a transaction hash.  Check the
# block explorer for confirmation.  Stop the program with "bitcoind
# stop" and restore your real wallet file.

#PUBKEYHEX={your public key}
#KEYPAIRHEX={your full key pair}
PUBKEYHEX=04ff5443fcd00b8f3844569dcaa42662d90e0c8afb1fe35804c320e5bb08ea6dadc3231767aa13b9dd6abcb45a8cd0497490d5c2a78ff85ea61711394b3b08e5c9
KEYPAIRHEX=fd170130820113020101042044b1585492c83e83fd917783c1b74ec25e3e6b3ca8722cc41eabe05249a46288a081a53081a2020101302c06072a8648ce3d0101022100fffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f300604010004010704410479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8022100fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141020101a144034200$PUBKEYHEX

# Replace "db4.7_load" with the name of the db_load utility installed on
# your system.
DB_LOAD=db4.7_load

# Output file name.
RECOVERED_WALLET=recovered_wallet.dat

# Refuse to modify a previously created file.
test -e "$RECOVERED_WALLET" && {
    echo "$0: exiting because $RECOVERED_WALLET exists" 2>&1
    exit 1
}

$DB_LOAD "$RECOVERED_WALLET" <<EOF
VERSION=3
format=bytevalue
database=main
type=btree
db_pagesize=4096
HEADER=END
 036b657941$PUBKEYHEX
 $KEYPAIRHEX
 0776657273696f6e
 027d0000
 0a64656661756c746b6579
 41$PUBKEYHEX
DATA=END
EOF

00003e80: 1a01 01fd 1701 3082 0113 0201 0104 2044  ......0....... D
00003e90: b158 5492 c83e 83fd 9177 83c1 b74e c25e  .XT..>...w...N.^
00003ea0: 3e6b 3ca8 722c c41e abe0 5249 a462 88a0  >k<.r,....RI.b..
00003eb0: 81a5 3081 a202 0101 302c 0607 2a86 48ce  ..0.....0,..*.H.
00003ec0: 3d01 0102 2100 ffff ffff ffff ffff ffff  =...!...........
00003ed0: ffff ffff ffff ffff ffff ffff ffff ffff  ................
00003ee0: fffe ffff fc2f 3006 0401 0004 0107 0441  ...../0........A
00003ef0: 0479 be66 7ef9 dcbb ac55 a062 95ce 870b  .y.f~....U.b....
00003f00: 0702 9bfc db2d ce28 d959 f281 5b16 f817  .....-.(.Y..[...
00003f10: 9848 3ada 7726 a3c4 655d a4fb fc0e 1108  .H:.w&..e]......
00003f20: a8fd 17b4 48a6 8554 199c 47d0 8ffb 10d4  ....H..T..G.....
00003f30: b802 2100 ffff ffff ffff ffff ffff ffff  ..!.............
00003f40: ffff fffe baae dce6 af48 a03b bfd2 5e8c  .........H.;..^.
00003f50: d036 4141 0201 01a1 4403 4200 04ff 5443  .6AA....D.B...TC
00003f60: fcd0 0b8f 3844 569d caa4 2662 d90e 0c8a  ....8DV...&b....
00003f70: fb1f e358 04c3 20e5 bb08 ea6d adc3 2317  ...X.. ....m..#.
00003f80: 67aa 13b9 dd6a bcb4 5a8c d049 7490 d5c2  g....j..Z..It...
00003f90: a78f f85e a617 1139 4b3b 08e5 c9bd ca00  ...^...9K;......
00003fa0: 4600 0103 6b65 7941 04ff 5443 fcd0 0b8f  F...keyA..TC....
00003fb0: 3844 569d caa4 2662 d90e 0c8a fb1f e358  8DV...&b.......X
00003fc0: 04c3 20e5 bb08 ea6d adc3 2317 67aa 13b9  .. ....m..#.g...
00003fd0: dd6a bcb4 5a8c d049 7490 d5c2 a78f f85e  .j..Z..It......^
00003fe0: a617 1139 4b3b 08e5 c9c2 57f9 0400 0102  ...9K;....W.....