Separating whites from colors when doing laundry is the number one rule to prevent color bleeding, but what about a shirt that has both black and white on it?

It's a known life hack to separate lights from darks when washing your clothes. But what about a piece of clothing with both colors?

Laundry expert Bernd Glassl from the German Personal Care and Detergents industry association doesn't beat around the bush when it comes to answering the question. "Such light-dark color combinations are rather inconvenient for washing," he says.

The expert recommends putting black-and-white pieces in with the dark-colored clothes, and to use a bleach-free detergent to protect the dark colors. It's also a good idea to wash the load in a cold water cycle.

The good thing about these color combinations is that the white parts often appear brighter thanks to the contrast with the darker bits.

To prevent the white from turning yellow or gray over time, Glassl advises using liquid heavy-duty or all-purpose detergent. This type of detergent does not contain bleaching agents, but optical brighteners.

These "absorb invisible UV light and emit blue light, thus compensating for a yellow tint of white textiles," explains Glassl. However, don't add yellow textiles to the load, not even light yellow ones, because detergents with optical brighteners may weaken these colors.

And next time you're debating putting clothes in with the dark or light load of laundry, you'll know what to do!