Exposing the original brick can be a great look for your space. I have definite opinions on the best way to achieve exposing your brick. The best way to communicate is by breaking it down into three categories.

1. Where Do I Do It? It might sound like an odd question, but there are two locations you should not attempt to expose the brick. The first is along an outside wall, obviously the front and back of the building. If you have a side wall that is also exposed directly to the outside, you shouldn’t expose that brick either. These walls should have some kind of insulation on them, therefore you should provide a framed wall at these locations. The other place one shouldn’t expose the brick is when the plaster is adhered so well that you begin to destroy the brick face removing the plaster. On a side note, you might also think about electric outlets. If you don’t want to have exposed conduit and outlet boxes along that wall, I would recommend at least a wainscot along the bottom to accommodate power.
2. How Do I Do It? The best way to remove old plaster is by hand. Don’t take any power tools to it or you will destroy the face of the brick and you won’t get the look you want. A good old rubber hammer is the best. Use as soft of a brush as you can get away with in order to achieve to end look. Don’t be too worried about mortar joints that are not neatly done as they add to the overall character. It is also fine to remove some of the mortar. You should take the areas you can remove all the way to the brick, but don’t worry about the plaster that wants to remain on the wall. Do your best to finish the edge of the plaster in order to get the look you want. Think like an artist while doing this and you will be happy with the end result.
3. What Can I Do to the Wall? You may need to fill in voided areas where brick falls out. Either mortar brick back in or fill the void with mortar. Be patient in finding the closest matches you can, otherwise it will stick out and draw attention. I have even stained the mortar before just to get the right match. Make sure you also fill in the gaps along the ceiling. This area will leak air, so it’s well worth the heating/cooling bill to fill. Mortar or drywall mud should solve this area. You will most likely come across wooden dowels embedded into the plaster. Leave them alone as pulling them causes more problems.