While you don't want to get rid of that authentic patina, you have to remove caked-on mortar, dirt, mold or mildew, and general staining. Thankfully, renewing old bricks is easier than you think.
However, its strength also makes it a bit of a burden when you want to remove mortar — don't forget, the Big Bad Wolf had no problem when it came to blowing down straw and stick houses ...