Over time, the light guides of Mercedes V-Class daytime running lights can suffer so that the light from the light sources at the ends turns yellow.
If this is already clearly visible, the light guide has been very badly damaged.
It can be restored, but depending on the extent of the damage, the result may not be as good as the original. The pictures show the result before and after restoration.
The best time to act would be when you can see even a faint yellowish tinge in the light. Then the light guide will have minor damage and the restoration will perform better.