When all of the donor parts come off of the car they're covered in rust and other general lovely stuff.
The thought of using a wire brush and other lovely chemicals sounded like hard work to me and to be honest I'm not that much of a fan that!

Fortunately Locostbuilders to the rescue! How to derust items with minimal effort

Items required:
12v power supply: A non automatic battery charger, non regulated 12v bench psu or an atx powersupply
A solution recepticle: Bucket
Solution: Water and Soda crystals.
Iron Anode: I used a coat hanger, Don't use stainless. It will release chromates into the water which is very dangerous.
Wire: to connect to Anode and Cathode
Cathode: Item you want to clean

Fill bucket with water to a level that will cover your item, then add the crystals. I had a batch of left over Caustic Soda which I used, however the recommended is Soda Crystals, purchased from Tescos for 51p! (Same aisle as washing powder)
I used 300g of caustic soda.

Place the Iron Anode in the solution, if you're using caustic then for heaven sake use gloves unless you want to lose your skin. I used a coat hanger as it allowed me to bend it completely around the item I wanted to clean.
The Anode must be connected to positive on the power supply.

Put the Item in the middle of the bucket and connect it to the negative side of the powersupply. All being well you should be seeing fizzy bubbles.

I used an ATX power supply from a PIII compaq deskpro, I'd tried some newer ones but they blew their internal fuses. To fool the PSU into thinking it's been turned on, I jumpered between pins 13 and 14 using a paperclip.

Depending on the size of your object it can take a while, using caustic and a not to rusty item took me about 2 hours.
Once the item is looking sort of rust free you need to rinse it off and then attack it with a wire brush to remove the last bits. They will fall off really easily. Using wirewool or similar you need to remove the black surface of the object, primer it and then paint it. It will corrode in the atmosphere very easily otherwise.

Here are the pictures I took of one of my uprights.

Cleaning Photos

Cortina upright as it arrived Electrolysis solution in use In the workshop sink (honest) Being primerd After 2 hours of electrolysis 2 minutes with a wire brush Modified compaq atx power supply