Iguanas as with other reptilians do not have the elasticity in their skin cells that mammals do, Therefore they go through a process known as Shedding.
What this entails is, a new skin is formed underneath the old one, and the older one peels away to reveal it! unlike snakes though Iguanas shed in sections, Maybe a leg arm and back first, then the head and tail...but this is a normal part of Iguana growth and shows in fact that they are growing well and therefore must be eating well.
Below are two pictures depicting Iguana shed.
This one is just about a complete arm!
Signs of shedding.
Some Iguanas are known to lose their appetite when about to start shedding, whereas others go through it with no problems at all.
First signs are, a change of colour of the skin to be shedded, this will often get a milky appearance or shades of grey, becoming more noticeable over a period of days, until the skin starts actually peeling away.
Do not try to peel off any skin that looks stuck, this can actually cause soreness where it is still joined rather like peeling off sun burnt skin.
Bathing and high humidity is beneficial and the Iguana will also rub the skin off himself on a log or the side of his habitat.
It is important that no shedding skin gets stuck on either the toes spines or tip of the tail, as this can have a constricting effect with build up of dead skin actually cutting off the blood supply, keep your eye out for any problems like this and help it come away with either frequent bathing, or rubbing in a little mineral oil daily to the difficult area, this will usually help release the stuck shed.