Things You'll Need
2 large buckets or wooden boxes
Hardwood: hickory, maple, cedar, ash or beech
Lye is a dangerous corrosive material, but it has a variety of benign uses. It is a used to cure dishes like lutefisk, pretzels, hominy, and the so-called "thousand-year-old" eggs in Chinese food. You can also use lye to make soap. Most lye today is commercially prepared, but in days past, lye was commonly made at home. With a little time, you can still make your own lye at home.
Fill a bucket with water. Write down how much water it can hold, as this information will be useful later. Empty the bucket and let dry.
Make an ash box. You can use either a ready-made container such as a large plastic bucket, or you can make your own wood box. In pioneer times, they used wood boxes for storing ashes and for making lye, but the bucket is less trouble. Your container should also have a tight-fitting lid. Drill a hole about 1/8-inch into the bottom of your bucket or box for water to drip through. Drill this hole into one side of the bucket instead of the bottom if you prefer. Make sure the hole in the side or bottom is slightly smaller than your nail, as you will be using that to stop up the hole.
Place your nail into the hole to plug it.
Burn your hardwood. Lye is made with wood ash, so you are going to need some good, clean ashes to put into your ash box. Once the wood is burned completely, let it cool for a day to make sure there are no hot coals hiding anywhere in them.
Put the ashes into the ash box. Spread the ashes evenly into the container. Don't place any unburned chunks of wood or coals into the ash box. As you burn wood, keep filling your ash box with clean ashes until it is full. Tamp the ashes down so that they are compacted and not loose. Place the lid on the box.
Get out the information you wrote down concerning how much water your ash box could hold. Boil half that amount of water. For example, if your bucket could hold 10 gallons, boil 5 gallons of water.
Pour the water over your ashes.
Place the other bucket or container close to your plug, where it can catch the water as it comes out of the hole. Remove the nail from the hole and let the water pour into the receiving container. Leave the receiving container there until all the water has gone through. This will take hours or maybe days.
Boil the collected lye water again. Wear gloves and safety glasses. Once hot, take it back to your ash bucket and pour it through again. This is to make sure the lye is strong. Collect the water into the receiving container again.
Test your lye water. One traditional method is to place a feather on top of it. If the feather dissolves, it's strong enough for soap-making.
Leave the lye water out in the hot sun until the water has evaporated. You should now have lye crystals.
Cardboard boxes will not work for your ash container as they aren’t sturdy enough and the water will make the box soft.
A thick, sturdy plastic box may work as an ash box, but be sure that the walls are thick enough to be drilled.
Use extreme caution around lye. Lye is caustic, and you can hurt yourself badly if you don’t handle it safely.