What the stain is made of determines what removes it.
The ketchup on the white shirt
The instinct with most stains is to scrub harder. Rub the spot with a towel, run it under hot water, throw it in the wash with extra detergent, and hope for the best. Sometimes that works. More often it sets the stain permanently, spreads it into a wider area, or damages the fabric in the process. A grease stain treated with hot water bonds to the fibers. A protein stain like blood or egg cooked by heat becomes nearly impossible to remove. A dye stain rubbed vigorously transfers to surrounding fabric. The common thread is that treating every stain the same way guarantees you will handle most of them wrong.
Type first, then treatment
Stains fall into a few broad categories, and each one responds to different chemistry. Protein stains (blood, egg, milk, sweat) need cool water and enzymatic treatment, never heat. Oil and grease stains (cooking oil, butter, salad dressing, cosmetics) need a solvent or surfactant that can break down fat. Tannin stains (coffee, tea, wine, fruit juice) respond to different approaches depending on the fabric. Dye stains (berries, mustard, ink) are among the hardest because the pigment is designed to color things.
The reading for this module walks through each category with specific treatments. The pattern that matters here is the diagnostic step: before you reach for any product, identify what you are dealing with. Check the care label on the garment. Test your treatment on a hidden area if you are not sure how the fabric will react. Work from the back of the stain outward so you push the substance out of the fibers rather than deeper into them.
The first question is not "what product do I use." The first question is "what made this stain."
Try it on something real
This module's action step does not ask you to memorize a stain chart. It asks you to find one stained item in your household right now, identify the stain type, choose an appropriate treatment from the reading, and attempt the removal. Record what you tried and whether it worked. Not every stain comes out, and that is useful information too. A household that knows how to approach stain removal and when to accept that something is permanently stained is better equipped than one that either ignores stains entirely or panics at every mark. The goal is not perfection. It is knowing the difference between a stain you can handle and one that has already set beyond recovery, so you spend your effort where it can actually make a difference.
The reading for this module
This is the core reading for the module. Take it with your earlier work beside you.
Find a stain and try to remove it.
Find one stained item in your household right now. Identify the stain type, check the care label, choose an appropriate treatment from the reading, and attempt the removal. Record what worked or did not.