Here’s how I do it.
I mix 50 grams of lighter fluid with an equal amount of acetone and any shampoo.
I dissolve all of this in one to two liters of water, and then I use a brush or cloth to wipe down the carpet with this solution, rinsing it off afterward with warm water.
It’s best to do this on a balcony or in the yard.
I’ve also used this same solution to clean raincoats.
I’m satisfied with the results.