If you are looking to get a raccoon out of your chimney, there are a variety of techniques to accomplish that task. First, you want to make sure that you actually have a raccoon in your chimney, and that it isn't something else (like chimney swifts, a duck, or some other bird. Raccoons commonly enter chimney's to raise their young in the Spring. Often, the first indication that you have a problem is when you hear a chattering sound of the young, or a growling sound of an adult raccoon.
Sometimes, people's first instinct is to light a fire in the fireplace. You do not want to do this because it will make your problem much worse. If it chimney swifts, then you may start a house fire. Also, the raccoon may have young that will not be able to escape without the help of the female raccoon. Starting a fire, may end up costing you more than hiring a professional from the start or using other techniques that only temporarily alleviate the problem.
Professionals have several methods to capture a raccoon in the chimney. There are a variety of chimney traps that slide into the chimney or that can be attached to the top of the chimney. These traps are expensive and have a different trigger mechanism than those that are used on the ground. Once the trap is installed in on the top of the chimney, the professional will either wait for the raccoon to enter the trap (which could take days), or they will use chimney cleaning rods/brush to chase the raccoon up the chimney flu and into the trap. Often, the next step is the most difficult. If there are young in the chimney, then they need to be retrieved, usually by hand. Professionals wear specialized bite resistant gloves for protection. Depending on the situation, this could be a couple hour project.
After the raccoons are safely removed from the chimney, you will want to prevent this from happening again. Many wildlife control professionals install professional grade chimney caps. These caps will prevent raccoons from becoming a problem in your chimney in the future.
There are a variety of other preventative measures that can be completed to reinforce your home from other possible raccoon entry points. You may want to ask the wildlife control professional about protecting common entry points through the roof ventilation points.