Lacto is also called Rejuvelac or probiotic water. You can make this literally for pennies. These probiotics have 1,001 applications from ingesting to treating fungal feet, pets, household cleaning, cleaning tools, and washing veggies and fruit. It’s a common product among homesteaders. Perhaps the main use is to repopulate healthy gut bacteria.
This method is hundreds of years old. It’s been used by a reputable NGO in Thailand for at least two years so I have high confidence it won’t make you sick. (Accidentally producing mold and bad bacteria is always a concern in recipes like this.) Some recipes leave you wondering if it’s safe.
Complete text details for making LACTO are shown below the video.
You can download a free manual that shows all the many uses. http://www.lacto-life.com/start-free
Also, you might want to check out natural building workshops at the Panya Project in Thailand.