I've now listed over 30 items in the space of a couple of weeks. My approach is methodical; I sift through all of my possessions, and anything I simply can't bear to part with (usually for sentimental reasons) I put to one side.
The rest goes into a metaphorical pile which I then get rid of by a variety of means. Some of it goes up on eBay to raise money for my travels - normally the hardware.
Some of it goes to charity to raise money for those that need it most - I donated more than half of my wardrobe (and we're talking designer labels here) to high street charities such as Cancer Research and Oxfam.
Most of the rest goes into the bin... but there's some stuff that ends up in a pile all of it's own.

This "pile" I'm going to put on eBay to sell. It will be the last thing I sell, and it will come in the form of a Mystery Box. The winner gets the key to the box, then a day or two later, the box will arrive (just to add a bit of tension, y'know?).
Along with the box and it's key, you also get a full inventory of the contents of the box and, most importantly, an explanation of why it's in there.

Now it's not called a box of mystery for nothing; you the potential buyer don't know what's in it.
Enticing, isn't it? To make it even more enticing, I will give cryptic clues to some of it's contents in the listing, and up front I can already tell you that if you were to win this "box", you would find yourself in possession of ancient artefacts, something that can play, something that can be played, and something royal.