Take a small tub - fill it with warm water - not hot. Put a tea towel in the tub with the water filled up about an inch. Put the snake in and pop the lid on. Leave to sit in a WARM place for about 30 mins. Take him out and run him gently (do not peel, let him do it) through the damp cloth over and over and over. Hold him firmly, but don't squeeze. This will get much of the shed off - if not all. If there is still shed remaining, repeat the process in 24 hours.
In order for his next shed to go well, be sure that the enclosure is constantly between 50-60% humidity, measured by a digital gauge. If you are having difficulty keeping the humidity up, let us know and there are a few things you can do to fix that. As soon as you see the dulling or opaque eyes next time, mist the tank until the humidity is approx 70%, and that will help ensure a good shed.