Ihave white fluffy mold on my brick fireplace in the basement. I have tried mold cleaner how do I remove it?

If your asking this question, you give me the impression that you don't know what you are dealing with. Your enemy here is water/moisture. Brick is porous like a human beings skin, the water penatrates thru the brick and what you are seeing there is a result of the bricks lime and mildew. First step, in the solution to your problem is to get an industrial quality mildew lime remover. Second, get rid of the moisture by a full visual inspection of your chimney's flue, check to see if you have a flue cap on top of your chimney , check to see if the flashing or roofing tile is intact and not damaged, if so replace. You may also want to add a brick or cement sealer outside of your chimney. Bottom line, your problem lies between one of those three.

i would first get a dehumidifier for the basement..it should help because it sounds like its too damp down there. you need to kill the source and then try a cleaner.

try spaying hydrogen peroxide from a spray bottle on it, and use a dehumidifier- they sell a water sealant paint at wal-mart that you can use to treat the concrete at the leak

Use a stick, or a lighter.

it is not mold it is "lime...part of the ingredients or your bricks' that is in their make-up to a grewater or lesser degree!!!!!it is "leached-out of the bricks by moisture....most likely the water that you have been applying to it or from an even more "issidious" source!!!it is perfectly natural;but if it bothers you ...find the source of the moisture;it could be a damaged flue or grating...an exhaust exit cap......bentonote paint seals and defray capillary water in some circumstances!!!like basement walls and pools!!!

Try mildew cleaner like you use in the bathroom.

it's not mold or lime....it's efflorescence or "white crust". You can scrap or wire brush it off and apply an acidic cleaner like Prosoco's VanaTrol. Then you can seal the brick with Silane or Siloxane WB ( also by Prosoco )