replying to Goedjn, JG wrote:
prose wrote:

The short answer is, once you stain a brick, you'll never
get it back the way it was. You can probably get whatever's
stuck to it off, at least mostly, but it's still not going to
look like the rest of the wall. That said:
Remove as much as you can mechanically, without damaging the
surface of the brick. Before you start to use chemical solvents,
saturate the brick with as much water as it will take, to limit
how much solvent/stain wicks deeper into the brick.
I don't think fire is a good technique for cosmetic cleaning of
brick, but maybe....
Before you start using fire on the surface, dry the brick completely,
else it's likely to explode. (although, replacing the brick
will likely solve the stain problem....)
http://www.bia.org/html/faqs.html#General
--Goedjn


I have found that the best way is to wait until winter then use a hammer.
This causes the tar to shatter and break away from the brick. I have not
tried to clean the stains yet.

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