To get the old skin off, soak him in some warm water for about 20 - 30mins. After this time you should be able to peel the skin off - it will slip off quite easy. Don't leave retained shed on him as it will dry and stick back down to his good skin. Multiple layers of old skins can cause skin concerns such as scale rot.
To help him next time round, when you see the signs of a shed - say when his eyes go blue - mist him every day with warmish water - not cold, he won't like it - until he sheds. This will help increase humidity and keep things moist to help him slip out of it.
Normally, jungles shouldn't require extra humidity but if you browsed some older threads you will see there has been plenty of talk about bad shedding this year. Many ppl have experienced it particularly because we've had such a dry winter (between the floods). So misting him daily during his shedding time won't hurt him. It will help him along.