In Jacksonville, FL, NE Florida and SE Georgia some of our customers are concerned about the black stains on the back of your fireplace.  These 
stains are more than just soot on the surface that a chimney sweep can easily sweep away.  The soot is cooked on and absorbed into the porous material on the back.  Some people remove it by pressure washing or sand blasting the brick or stone.  Some of our customers have had success with a stain removing spray cleaner and lots of elbow grease - if the stains aren't too bad.  But remember, with your very next fire they will come back.  A regular chimney sweep does not include cleaning these stains.  Your yearly chimney sweep is not for the looks of the fireplace but more for safety.  The chimney sweep removes the  soot from the flue before it becomes flammable creosote and therefore prevent chimney fires.   Even of a chimney sweep could remove the stains in the firebox they would be back with your next fire.  Our advice is to use the chimney sweep for safety and embrace the stains as part of the character of having a wood burning fire in your home.  When the chimney sweep is there cleaning your chimney you can ask him to take a look at your fireplace stains.  The chimney sweep may have some advice more specific to you.  Don't let the stains keep you from having a chimney sweep clean your chimney every year and make your chimney and fireplace safe. 

Please note the stains we refer to above are inside the firebox, where you build your fire.  If you have soot stains on the wall above the firebox and on the mantle your chimney is not drawing properly and you should have it inspected by a chimney sweep.