have found cleaning the bricks with an all natural citrus based cleaner/degreser works well. They also make a sealer for the bricks after they have been cleaned to give them a soft shine and it will help keep them clean. If you can find this product called Mex made by UGL the company that makes DryLoc it works great to.

Here is a link that might be useful: Mex Cleaner

We use vinegar on our bricks and I think they look great...

I used a concrete cleaner with a very stiff brush, worked pretty good. But I liked the idea of vinegar, will try that next.

I use the foaming bathroom cleaner. (like Mr. Bubbles) I actually saw this on HG-TV show and it does work. I bought some cleaner last year at Lowe's and scrubbed and scrubbed above my fireplace and could not get rid of the soot. So back in the summer I saw them use this bathroom cleaner so I gave it a try. It was amazing. I actually just bought the store brand and it broke the soot down and it was just running down the brick. Pretty amazing. It didn't bother the brick at all.

Vinegar is a great cleaner, however it is a liquid containing acetic acid. Once you use it to do what ever it is you are using it for, you should use water to neutralize its effects.