Lye, or sodium hydroxide, is one of the oldest used paint strippers. These days, however, there are a lot more effective types of paint strippers available at your local paint store. Because lye can dissolve glue and make wood soft, it is generally not a very useful chemical unless you need to remove a particularly stubborn paint stain or you need to strip a large amount of paint from a very large surface. Because lye can burn skin, you need to know the proper way to use it or you may end up having to visit the emergency room with severe burns.
Put on acid-resistant gloves.
Work outdoors or in a well-ventilated area.
Fill a 5-gallon bucket with two gallons of water.
Stir in one cup of lye powder and one cup of cornflour using a wooden stir stick.
Apply the solution to the surface using an oil-based paintbrush.
Allow the solution to soak into the paint for five minutes.
Scrape away the paint using a metal putty knife.
Apply a solution of one-part vinegar and one-part water to the surface, effectively neutralising the lye.
Rinse the surface with a water hose.
Neutralise the solution in the 5-gallon bucket by stirring in three cups of vinegar.
If you are working indoors, you'll need to use a respirator with acid-grade filters.
If lye touches your skin, it can cause a chemical burn. Always wear protective gloves when working with lye to avoid unecessary injury.