Worked in HS for a local computer repair shop. One trick to improve success with the freezer method is to place the drive in a sealed plastic bag with some desiccant packs. Placing a bare drive in the freezer can kill it due to condensation. Leave the drive in the bag at least a few hours to give the desiccant time to work. Like others have said, this is a last ditch effort, and if you really care enough, don't do it if you are willing to send it to a specialist, since it can ruin a recoverable drive. But it does seem to work ~30% of the time (at least w/ deathstars) and I did have success on a clicking Seagate drive last year.