but I have to disagree with you - not all cracks are a sign of weakness (i.e. one reason why one puts control joints in, etc...) Granted the "widening" can cause one to think that but with the way the question & reply is worded I am not positive at this moment; not only where they are much less the size, thus the do you have pics. Good point on the warranty - if they say no then you know the problem is bigger than just a superficial crack

than adding more water. A thin putty knife or old screw driver could also help clean out the cracks. No sense adding water to a water induced problem. Once all of the debris is out you will not need to wait for it to dry.

wear some safety glasses or goggles the air will send small bits of sand + dirt flying.

around the concrete and have storage for coats,shoes etc.You can put doors on them or make seating below and cabinets above.Actually any type would work because you can back it to cover the brick. Good luck!

and some cleaners to remove any soot stains. To much can cause the soot to bleed into the bricks making it even harder to remove. Also chemicals can be dangerous to use. Fume build up can get you quite sick. I would suggest going the route that Kevin stated a brick and stone cleaner.

Do not expect to get the bricks really clean. Being porous as they are the soot can easily get into the brick and not come out.

I would suggest to take photos of the front of the fireplace before you clean. Then show them to a professional chimney sweep if you clean the fireplace before they come by. A properly operating fireplace should not soot the outside of the brick if its properly constructed and sized. Fixes if there are issues can be as simple as a glass door or panel front to decrease the overall opening in the front, to extending the fireplace chimney higher to generate additional draw to pull the soot spillage into the fireplace instead of allowing it to spill out.