What will happen if heat is applied to a stain?

When heat is applied to a stain, it typically causes the stain to set, making it more difficult to remove. This is particularly true for many types of organic stains, such as those from food, beverages, or bodily fluids. The heat can cause the proteins or pigments within the stain to bond more tightly to the fabric fibers, creating a hardened or more permanent discoloration.

In many cleaning scenarios, it is often recommended to treat stains with cold water first, as applying heat can exacerbate the problem instead of remedying it. Therefore, understanding the effect of heat is crucial when dealing with stains, as it plays a significant role in the stain's behavior and removal process.