Some would wonder why anyone would ever paint brick, and before you commit to removing the white paint from your bricks, you should consider the possible reasons why the bricks are painted. That brick may have been damaged or discolored from wear and tear or repair projects completed over the years that left unmatched mortar joints or bricks.
If you still wish to move forward with removing the white paint from the bricks, the most popular paint removal options are pressure washing and sand blasting. Unfortunately, these are the most destructive and I don't recommend them. Both options can dig into the brick surfaces and mortar and leave them permanently damaged. Plus, grinding away portions of the hard exterior surface will also leave the brick more susceptible to moisture and the resulting frost damage.
The best option for removing the white paint from the bricks is a peel away chemical stripper. It is a slow and tedious process, but it will do the job. Before you commit to stripping the entire painted brick area, try it out on a small area to get a sense of how well it works and what the brick may look like underneath. If it turns out to be more work that you counted on, or if the brick isn't what you expected, you can always opt to repaint the bricks.