Those are some madroños from the Mercat Central here in Valencia.
I remember going there in 1998, the first time I came to Spain. It was February, and there were no madroños.
Anyway, the fruit lady told us to eat them as-is. No washing. No doing anything to them.
We followed her instructions.
La que quiera madroños vaya a la sierra
olé Morena vaya a la sierra
porque se están secando sus madroñeras
olé morena sus madroñeras