With the aid of a strong magnifier and using a small flat bladed screwdriver (the type used for spectacles). Insert the screwdriver, carefully, between the chassis and the outer rib on the body above the axle box, the one the opposite end from the hand brake lever (so as not to damage the lever); you only have to lever the body out about half a mil., then do the same on the next rib pulling the chassis down slightly and it will start to release. Once it starts to release, do the same on the other side, there is nothing else to release, just the four clips that hold the body onto the chassis. I managed to do all four wagons with no damage. As a footnote I've added 25 grammes of weight and they run and feel so much better. Just take it very carefully. Cheers Neil.