The procedure is very simple and straightforward.
What you need
1) Sugru, I used three packets (1 Blue, 1 RED and 1 Blue)
2) 4 Key Cards
4) Plastic modelling knife
Wash Hands in order to keep the sugru clean
For the first two key cards I selected some red sugru. I rolled out a small cylinder of sugru which would be enough to wrap around the loop of the key card. I then joined both ends and smoothed the sugru.
For the other two key cards I wanted a brown colour to match the colour of the car. I didn't have any brown sugru so I tried a mix of Red, Yellow and Blue which worked well and gave me the colour I was after. Again it was just a matter of rolling out a small cylinder of sugru which was enough to wrap around the loop of the key card. I again joined both ends and smoothed the sugru.
I left the cards overnight and they were fully cured the next day and job done!