Yellow stains are one of the stubborn stains that laundry shops frequently encounter in daily tasks. When facing yellow stains of different origins and properties, relying only on a single method or blindly using bleach is ineffective and may cause damage.
Identifying the type of yellow stain and using the correct treatment can improve stain removal. It can also help ensure the safety of clothes.
Guide to Identifying Yellow Stain Type
Common yellow stains can be primarily analyzed in terms of three dimensions: location, touch, and color.
- Location
– Collar, cuffs, underarms
They are mostly a mixture of sweat stains and sebum.
– Front chest, placket area
They are commonly oil stains or colored liquids (coffee and juice).
– Uniform yellowing of the entire garment
It is usually caused by oxidation during long-term storage.
– Spotted or flaky stains
These stains might be oil spots, or they could come from spilled drinks.
– With mold spots or powdery substances
It is a typical sign of mold stains, and is mostly caused by storage in humid environments.
- Touch
– Stiffness
It may result from the combined effect of stubborn sweat stains and oxidation.
– Sticky feeling
It is typically oil-based stains.
– Removable powder when wiped
One of the characteristics of mold stains.
- Color
– Yellow with reddish-brown tint
Common in oil pigments, protein oxidation stains (blood stains, milk stains), tannic acid oxidation stains, or rust stains.
– Light yellow with lemon-green tint
Mostly plant tannin pigments, such as grass stains, lemon stains, curry stains…
Categorized Treatment and Stain Removal Process Recommendations
Here is an important pre-treatment note. Regardless of the stain remover or method used, operators should always test it first on a hidden area of the garment to check for color fading or fabric damage.
- Yellow stains with reddish-brown tint
– Oil pigment stains
First perform oil removal treatment, then use chlorine bleach or oxygen bleach for oxidative bleaching.
– Tannic acid oxidation stains
First treat with stain-removing acid, then apply oxidative bleaching (chlorine bleach/color-safe bleach).
– Protein oxidation stains (blood stains, milk stains)
It is recommended to first decompose with a protease preparation, then treat with stain-removing acid, and finally conduct oxidative bleaching.
- Light yellow stains with lemon-green tint
They are mostly plant tannin pigments.
Treat with stain-removing acid → apply oxidative bleaching.
- Precautions for common stain treatment
– Protein stains (sweat stains, milk stains…)
Do not use hot water, as it will cause protein coagulation and increase the difficulty of removal.
– Beverage stains (coffee, tea, fruit juice…)
First spot-treat with an alkaline emulsifier, then alternate treatment with stain-removing acid, and finally perform oxidative bleaching.
– Storage-induced yellow stains
These are stubborn stains; it is recommended to use an alternating treatment method with oxidizing agents and acidic reducing agents.
– Mold stains
It is recommended to first locally treat with a stain remover containing ethanol disinfectant, then wipe and follow with oxidative bleaching (oxygen bleach or chlorine bleach).
Operation Recommendations
– Timely Treatment
The newer the stain, the easier it is to remove.
– Testing First
Always do a small-scale test before any stain removal operation.
– Categorized Operation
Select appropriate treatment agents and methods based on different stain types. Avoid the overuse of bleach.
Conclusion
Kingstar is always dedicated to providing professional technical support and advanced laundry solutions for the laundry industry. We hope that every laundry industry practitioner can use scientific, highly efficient, and safe methods to encounter all kinds of laundry problems, improve service quality, and customer satisfaction.
