The crux of the issue here is that a waifu is imagination personified. By definition, she is how you fantasize her, and this thought is aided in taking form through a personality set forth in the original source material she came from. The healthy man knows he is imagining his waifu, and accepts this.
Definition of lye. 1 : a strong alkaline liquor rich in potassium carbonate leached from wood ashes and used especially in making soap and for washing; broadly : a strong alkaline solution (as of sodium hydroxide or potassium hydroxide )
Lye soap is a cleaning product that is made using lard, water, and lye. It was historically used around the world before commercially produced soaps became commonly available, and is still used by many people because of its potential benefits for skin and because of its all-natural recipe.