The biggest problem with using a pressure washers come from inappropriately choosing the wrong tip. For instance a "zero tip" will dig a horrible hole, which is just terrible unless you are attempting to drill a hole for an anchor iron to hang something. The zero tip could cut off someone's finger if it were used as a weapon. Another common tip to use is the 15 degree tip, most all pressure washers, even the little electric, Chinese built home units often have these.

And although these little units only have 800 to 1500 psi, with a zero tip, if you get too close to the natural stone you can very easily cause permanent damage. Thus, I recommend keeping the pressure wand 12 inches away at all times when cleaning natural brick and to choose a 25 degree tip or larger, I recommend a 45 degree tip just to play it safe.

The second problem with folks that clean natural brick is using the wrong chemicals that can permanently stain the brick, so it's best to use a semi-hard bristle brush, soap and water and a 45 degree pressure washing tip at the end of the gun or wand.