First it's helpful to understand what's happening in there. See the hole where the wires and spades engage the plastic body of the connector? Notice that is has a very slight T shape?

There is a small tang on the spade that clicks into place when the assembled wire and spade is inserted. To remove this wire/spade combo, we must push the tang out of the way momentarily:

So we need this, or a facsimile thereof. A pick or jeweler's screwdriver works but requires a bit more feel. Select the size pick that most closely matches the connector:

Insert along the base of the T. It's helpful to push the wire/spade assembly into the connector from the opposite side a little as you do this so the tang isn't binding against the plastic. Push the tool in till it stops, hold it there, and remove the wire. This would be a good time to make a really foolproof diagram showing what wire goes where in the connector


Assembly back into an identical connector is simply a matter of sliding the wire/spade back into the plastic connector until you hear it click into place. You should make certain the tang is standing proud of the spade and not smushed flat from your extraction process.
If you need to replace the spades or sockets for whatever reason, then there is a second operation. Note that not all spades or sockets will fit all connectors. Be careful to match them up.
These spades and sockets have a little strain relief designed into them, to crimp the insulation of the wire as well as the wire itself.

Strip a small amount of wire (I actually did too much here, 2-3mm or so is about right)

Insert the wire into new spade so the insulation is on the outermost crimp point. Crimp it carefully, and not all at once, eg you may need to work the metal into a cylindrical shape with the tip of the crimping tool a bit before you smush it down or it won't come out right. You will see what I mean the first time you do it.

Crimp onto the insulation to provide the strain relief. Don't mash it too hard.

Crimp onto the stripped part, as above.

For the BEST results, wick some solder into it now. I didn't show this in pictures, I was too lazy to fire it up.
Reinsert into the connector, and hear it snap into place.
You need some stuff:
These connectors can be found at Vintage Connections http://www.vintageconnections.com/

Likewise these tools:


I love my stripper (hush now!), can't recall where I got it:

Suggestions welcome!
N.