Lemme Google that for you since you don't know how too.
"In the old days, traditionally shampoo is made from rice husk and rice straw (merang). The husks and straws are burned into ash, and the ashes (which have alkaline properties) are mixed with water to form lather. The ashes and lather are scrubbed into the hair. However, this makes the hair dry. Therefore, after shampooing, Indonesians apply coconut oil to remoisten the hair."
What did people use before shampoo