Fireplace brick can discolor over time from exposure to soot, smoke and ash debris, all of which take away from the natural beauty of the fireplace, not to mention the overall design aesthetic of a room. It takes some time and a little elbow grease to get the bricks looking like new, but the results are worth it.
Because bricks are a naturally porous surface, much of what you’re identifying as dirt could actually be the gray or brown shadowing within the brick, and not just on it. As a general rule there are 4 types of cleaning needed on fireplace brick. The first (and easiest) is mud/dirt and ash. It may need soot removal or be stained by smoke. There may be small areas of creosote, especially if your fireplace has glass fireplace doors.
An effective approach to getting the area clean is to use ingredients, such as soap, salt and baking soda, that will draw the soot out of the brick and remove a very thin layer of the permanently discolored surface material to expose the clean area underneath.
Smoke and Soot Debris on Brick:
Smoke is a difficult stain to remove. Try scrubbing with scouring powder (preferably one containing bleach) and a stiff bristle brush. You can also try alkali detergents (such as some powder laundry detergents – Karcher, Simple Green and Central Wash) and commercial emulsifying agents; apply these with a brush or spray and be sure to give them sufficient time to work. Test these chemicals on a small area that is not too visible before using them on a large area. (These compounds have the added advantage that they can be used in steam cleaners.)
For small, stubborn stains, a poultice using trichloroethylene will pull the stain from the pores. Exercise caution when using trichloroethylene in confined spaces. Ventilate the fumes.
For small areas of soot, press light-colored children’s molding dough onto the brick and lift the soot away. (Be careful–you don’t want to pull off any surface material.) Or dip a scrub brush into a pan of full-strength white household vinegar. Scrub a small section at a time, working up. It may take a lot of elbow grease and several applications to remove all of the soot.
Read more: Brick A-New
Here are some helpful tips as you make the proper preparations to clean your fireplace brick.
-Stiff bristle brush
-Trisodium phosphate (for heavy-duty jobs)
Instructions on Cleaning Brick:
1. Put down a layer of plastic sheeting and then cover that with newsprint.
2. Clean the inside of the fireplace and remove any ashes.
3. Remove the fireplace screen, andirons and any other decorative objects.
4. Cover nearby carpeting, furniture and draperies. Brushing can spray specks of soot long distances.
5. Open the windows and fireplace flue to make sure that the area is well ventilated.
Scrub Brick With Mild Abrasives
6. Make a mixture of equal parts dishwashing liquid and baking soda or salt.
7. Rub the paste onto the discolored brick surface with a cloth, making sure to get it onto the mortar and in all the crevices. Be generous.
8. Allow the mixture to dry completely to give it time to draw out some of the soot.
9. Brush it off in long strokes that blend into the surrounding brick. Consider this as a first and last step. The baking soda will help neutralize any acidic cleansers you may have to use.
10. Rinse with warm water.
Scrub with TSP
11. Mix trisodium phosphate (TSP) cleanser with water according to the manufacturer’s instructions. TSP can be caustic; it’s a powerful cleaner, so wear gloves and eye gear.
12. Brush TSP on the brick and scrub with a stiff brush.
13. Allow the area to dry between applications.
14. Evaluate any remaining discoloration. You can apply TSP more than once and increase the concentration if you have to.
15. Clean the spot thoroughly with water.
Tips & Warnings as You Clean Brick:
In addition to the above preparations, there are also fireplace-cleaning solutions such as Brick-Anew that can get out stubborn spots. For a multitasking solution, use oven cleaner to get spots off your brick fireplace surround. It works in the oven to remove the same type of buildup. If soap and a mild abrasive are getting most, but not all of the discoloration off, try again but add a little ammonia to the mix.
Matching the brick surfaces around the discolored spots is your objective, so take it easy and keep that in mind as you scrub. The methods suggested here go from the least to the most aggressive, and you should always use the least aggressive solution that will still do the job. Before cleaning your brick fireplace surround, test a small, inconspicuous area to be sure it will give you the results you want. Strong cleaners can discolor mortar and even change the shading of the brick itself.
Read more: How to Clean Fireplace Bricks | eHow.com