At the edge of the Medina, by Bab Debbagh are the tanneries where you can observe the process of tanning and drying skin. … The process involves tanners treading and rinsing skin in large vats of dye and pigeon dung, while other artisans scrap and stretch the skins to dry. The tanneries are very similar to the ones in Fez, although they are more scattered making it less of an interesting experience. The best time to visit is in the mornings, when there is most activity. To get a good view of the proceedings, use of one the shops with terraces overlooking the tanneries.