Tannign leather was actually worse than that. The process could take over a year to complete in early times. it was not until the Middle Ages that anyone discovered the couple-month-long process!
Pieces of broken amphorae (and there were a lot of them, the amphora having been the preferred vessel for transporting liquids) were just tossed on a big pile, which over time accumulated to form a mound. It is still visible in Rome, known as Monte Testaccio, and although it’s not possible to climb it (it’s enclosed by a fence), it is clearly visible that this hill actually consists of ceramic fragments.