There are a lot of laundry detergents today and you can find dozens of different brands within the same price range.
You never know their quality; for example, some just don’t wash away the stains, others make light linens gray. You can struggle for a long time choosing a detergent if you don’t know the following interesting secret.
To check the quality of laundry detergent you need to dilute a bit of powder/liquid in a glass of water and put a piece of hardboiled egg white inside. If the egg white remains intact after 24 hours, this detergent is bad. If it softens and begins to dissolve a bit, this detergent can be used to wash dark clothes as well as lightly soiled ones. And if the egg white gets completely dissolved, feel free to use this detergent for white and heavily soiled things!
You can also check the quality with a different method:
Take 2 glasses each half-filled with water, add a little bit of detergent from questionable packaging to one glass and a high quality detergent to the second one, add 3 drops of brilliant green (Viridis Nitentis) to each glass, mix, and observe the color of the water in the glasses.
Brilliant green will dissolve and become discolored in the glass with a high quality detergent and will remain unchanged in the glass with a poor quality detergent.