Sodium hydroxide (or lye) and water is a powerful paint stripper originally used to remove lead paints. This at home solution is just as strong as anything you could buy at the store and just as toxic. It's important to use extra caution when using toxic chemicals. Sodium hydroxide solution is not recommended for use on wood or in closed areas. Sodium hydroxide is great for removing paint because it will strip everything it touches. So don't wear your favorite pair of jeans when using sodium hydroxide solution, unless you want holes in them.
Go to the hardware store and buy a bottle of sodium hydroxide. It also know as lye or caustic soap.
Put on your protective breathing mask and rubber gloves.
Get a large bucket and add about four cups of the sodium hydroxide to every gallon of water. If you want a stronger solution you can add another cup of sodium hydroxide to the solution. Take extra care not to splash the sodium hydroxide on your skin because it can cause serious chemical burns.
Use a mop to cover the areas where you want the paint removed with the sodium hydroxide and water solution. Take extra care not to get the solution on anything that you don't want stripped. For more detailed areas, you make want to use a small sponge.
Let the solution sit on the wall until the solution has dried. You should notice the paint cracking and peeling. At this point it should be easy to chip off with a metal spatula.