A cheap way to kill lice is bury the infected clothes under small stones as shown in the photo below.
After a few hours all the lice is dead, and your clothes are essentially disinfected. No more itching down there, and having lice eggs hatched all over one’s pubic hairs.
Eritrean soldiers used this system for years during their civil war when soap was scarce.
One way to kill lice, which were rife among soldiers, was to bury clothes under small stones, a war veteran told me.