Locating old Debian source packages

So you want to import your pet package into the new and shiny VCS of the day, but you don't have the complete source history at hand, and some of the revisions are too old to be on snapshot.debian.net or were never part of a Debian release and aren't on archive.debian.org?

Here's an easy way out:

1. For each missing source package, look into the debian-devel-changes archive for the MD5 sum of the corresponding .diff.gz file, it's present in the mail sent by katie.
2. Google this MD5 sum. If your source package is sitting somewhere in the ether, the dsc file contains the sum and Google probably indexes it.
3. Fetch your source package, check the signature on the dsc and the integrity of the .diff.gz. If everything looks good, go to step 1.

For the record, I found some of mine on old-releases.ubuntu.com, apt.freespire.org and these snapshots.