1 bar of Marseille soap
120 ml of white vinegar
1 tablespoon of baking soda
3 liters of water
kitchen grater
clean bucket
Procedure:

Grate the bar of soap into the bucket.
Pour a liter of water over the soap until it is completely covered and let it sit overnight.
The next day, pour the contents of the bucket into a saucepan, add the remaining 2 liters of water, and mix with a wooden spoon. Then add 120 ml of white vinegar and 1 tablespoon of baking soda.

As soon as it starts to boil, turn off the heat and wait 10 minutes.

Let it cool for 20-30 minutes, then pour it into the final container.
Use the liquid detergent the same way you would industrial detergent. You’ll see how much cleaner and fragrant your laundry will be.