Non of us snake keepers like those bad sheds. Here are steps to avoid a bad shed and steps to assist your snake in shedding if it happens to have a bad shed:

ACHIEVING A GOOD SHED
We all love it when we see that complete shedded skin. No pieces around, just a nice, clean piece. If your snake sometimes sheds in pieces, here is how to get them back on track.

When you just notice your snake is in shed, it's time to cover up the enclosure sides. If you have a glass enclosure, cover all sides with a towel or bed sheets (except the top of the enclosure). If you have a vision cage, only cover the one transparent side with a towel or bed sheet. Keep all sides covered until the snake sheds. Keeping the sides covered reduces stress on the snake since it cannot see well when in blue. Next, keep the humidity level up so the snake can have an easy shed. During this time, you may notice your snake soaking in the water dish to loosen up the skin. Also, try not to handle your snake the entire time while shedding because that increases the stress of the snake. Some snakes may be moody when shedding because they cannot see well so it's best to let the snake be while shedding. For the first two days, soak the snake in warm water in a container for about an hour. This helps loosen up the skin for a good shed. When your snake sheds, it will most likely come out in one whole nice clean piece.

ASSIST SHEDDING YOUR SNAKE
When your snake sheds, and you notice there are still some pieces left, it's time to assist shed. Soak the snake in warm water for about 10-15 minutes. After you have soaked the snake, it's time to remove the left over skin. Slowly and gently pulled the skin backwards (like the snake does when shedding itself) so you do not pull off any scales that were still stuck to the shedding skin. When you are pulling off shedding on the head and face, the snake will be a bit nervous so don't get scared if the snake is trying to move it's head around to get away. When taking off eye caps, do this very slowly and gently so you do not harm the snake and cause serious injury. That is how you assist shed your snake, and the safest way. If you still have problem trying to get the skin off, there are products at your local pet shop that will help you get the skin off.