Very few tools will correctly wipe hard drives that are connected via USB or FireWire, the two most common external hard drive case connection technologies. Incorrectly wiped drives can still have their data recovered.

One of the best ways to wipe a drive is to download DBAN http://sourceforge.net/projects/dban/files/dban/dban-2.2.6/dban-2.2.6_i586.iso/download, create a CD-ROM from the ISO, and boot the computer from the CD-ROM. Be warned that this will destroy all data on the hard drive. This will work even if the password is forgotten, as long as it's not the BIOS password.

A low-tech method that's sometimes easier is to drive four or five ten penny nails through the platters. Make sure that you start on one of the two largest sides by area, and drive the nails all the way through in several different places. This precludes the re-use of the drive.

The most paranoid method I know is to disassemble the drives and use a grinder or wire brush to remove the thin magnetic coating from the platters.

Don't wipe hard drives.

HDs used to be expensive and the odds of unwiped data being exploited were small. Now HDs are cheap and the odds of unwiped data being exploited are much higher. HDs, even large ones go for a few hundred dollars whereas identity theft can cost you thousands of dollars and months of effort.

HDs are also much larger than they used to be so any wiping program takes much longer. A terabyte drive can take a very long time to wipe. Particularly when you use any of the better multi-pass procedures.

Save yourself time and effort and absolutely remove any chance anyone will find any data left behind by pounding your unwanted HDs discs to rubble. Takes about two minutes with a hammer if you don't disassemble the HD. Once the discs shatter they are essentially impossible to read by conventional means. No need to acid etch or wire brush anything. Disassembly takes another five minutes. As a bonus, once disassembled you get a nifty magnet to play with.

SSDs use an entirely different storage technique and they are both easier to wipe, harder to recover any wiped data from, and there is no need to destroy them to keep the data safe. A good thing because SSDs are still expensive.

Added a few sentences for clarity.

I am trying to find a place to do decent scans to DVD of old pictures, diplomas, certificates, etcetera. Then my resolve to recycle the originals will be put to the test.

Computer-related stuff is about the easiest stuff to organize.

It's harder to organize (get rid of) "macro" things, such as books, musical instruments, art work, board games, momentos, R/C cars, skates, skis, stereos, toys, VHS tapes, CDs, vehicles, etc.

I am simultaneously working on my survival stuff. The large entry area of the place I am house-sitting looks like an equipment bomb wnt off, complete with all my kayak and diving gear.

I look what is in storage and if it duplicates survival stuff in hand, the less well-built, less multi-tasking, bulkier gear goes away - most of the time. Some finds a home in new kits I feel I should add, such as winter camping distinct from 3-season camping [I am in California].

I stare at piles of stuff hoping for inspiration, and often then go get something to eat. Nothing is easy.

Dweste, kit builing is like reading a choose your own adventure Book. Everytime I open one up I get a different ending!

Personal note: most kits, or their sub-kit components, must fit through an 8-inch diameter round kayak hatch and be no longer than 14 inches. Exceptions for arsenal, diving, and severe camping gear, which fit a much larger front hatch.

Trying some vacuum bags. Volume reduction, yes; will the vacuum last, uncertain.

Often consider a vacuum sealer, but budget concerns.

Or you can opt for the Do-it-yourself method. Ziplock freezer bags and a straw. Suck and seal. Or compress and seal without the straw. Some clothing items and the toilet roll in my car kit stayed vacuum sealed for a year that way.

Assembled well over 20 knives, from machetes to specialized folders. Not including several multi-tools that have blades.

Did not think to include kitchen knives, so its back to searching for those in the sailboat "galley" and the ice chest galley "storage locker" onboard.

I will have to answer important questions like, do I really need an oyster knife?

Who the heck bought all these things?