Egg stain
Almost pure protein, and the clearest case there is of hot water making the problem permanent rather than smaller.
In detail
Egg white is close to pure protein in water, and egg yolk adds fat and pigment. It is the textbook protein stain, and it demonstrates the rule better than any other because everyone has watched the mechanism happen in a pan: heat denatures the protein, it changes shape irreversibly and it sets. Applied to a fabric or a carpet, hot water does the same thing on a smaller scale and bonds the protein into the fibre. The treatment is therefore cool water and patience, with an enzymatic product if one is available, because a protease digests the protein into fragments small enough to rinse. The carpet institute's egg entry runs detergent solution, vinegar solution, warm water and then an ammonia solution, with no solvent step and no hot water anywhere. On vehicle paintwork egg is a genuinely urgent problem for a different reason: the proteins and the alkalinity etch clear coat within hours, especially in sun, so the priority is to soften and flood it off quickly rather than to scrub it, which drives shell fragments across the finish.
Why
- Egg stain is explained by Protein denaturation
- Egg stain is explained by Heat-set stains
Sources for this page
Sources
Spot Solver: spot and spill removal procedures
The Carpet and Rug Institute (CRI) · Trade or professional body
Relied on for: That the egg entry runs a detergent solution, a vinegar solution, warm water and an ammonia solution, with no solvent step. (states this directly)