When the Muppets took Manhattan, Kermit the Frog created an advertising slogan for soap: Ocean Breeze Soap Will Get You Clean. What he didn't realize is that another slogan would have been just as accurate: Ocean Breeze Soap Will Blow You Up.
Soap is all over the place in Fight Club. Let's take a look:
• The glycerin from soap can be used to make nitroglycerin, and boom goes the dynamite.
• Fat from people (like Marla's mother) can be manufactured into lovely soaps. (Paper Street Soap is people!)
• And most importantly, Tyler gives a long speech about the history of soap, and its connection with human sacrifice: "The first soap was made of heroes. [...] Without their death, their pain, without their sacrifice […] we would have nothing" (9.57, 9.60).
Think about that the next time you go shopping for Irish Spring.
So besides letting us know that we should be extra careful in the shower, what does all this sudsy sacrifice boom-boom stuff mean? Well, it shows us that a couple key themes of fight club—human oppression and the sacrifice of the poor for the benefit of the wealthy—go way, way back. Through the use of soap, Tyler is inverting these ideals in order to spin the world upside down. Stealing fat from the rich and selling it back to them is an act of Robin Hood at his most twisted and subversive.
Fight Club might be the only book on the planet where soap and pee are not only both used as recurring symbols, but they kind of mean the same thing. Let's take a look:
Cultures without soap, Tyler says, they used their urine and the urine of their dogs to wash their clothes and hair. (9.51)
And we thought Neutrogena T-Gel shampoo smelled bad.
Anyway, the point: urine, like soap, can be used for cleansing.
Tyler likes to do things a little differently, though. He's not looking to cleanse his body; no, he wants to cleanse the world of the upper class and all the arbitrary rules of society that go with it. How does he do this? By peeing in soups and desserts at the Pressman Hotel. When catering a party, he leaves a note telling the hostess, "I have passed an amount of urine into at least one of your many elegant fragrances" (10.31). Sure, he didn't do it, but the principle is the same. Our narrator even dreams that he's "pissing on the Blarney stone" (9.46). We don't know what the Blarney stone did to him, but yowza.
When Tyler and his Project Mayhem cronies threaten to castrate government officials, these poor guys usually pee themselves. Looks like Tyler's tactics are working. Pee on the world, make it a better place, we guess.