Graphics: Oliver Lüde / CC: Museum für Gestaltung Zürich, ZHdK / plasticgarbageproject.org No more messages in a bottle For generations, blue water cruisers have separated out garbage underway to dispose of the "degradable" items from garbage into the sea. Food scraps were definitely in that category, as was paper and glass. Metal tins were often considered degradable as well, given how quickly things rust away if left on their own. But no more. MARPOL Annex V adopted for international waters as of January 2013 delineates that discharge is prohibited of plastics, synthetic ropes, fishing gear, plastic garbage bags, cooking oil, lining and packing materials, paper, rags, glass, metal, and bottles.