Conventional sponges are made from synthetic materials like polyester or polyamide, and as they wear down they release tiny plastic microfibres that flow down the drain and end up in rivers, seas and oceans. Switching to a coconut fibre or luffa scrubber puts a stop to that: every time you wash up with a conventional plastic sponge, microparticles are released into the drainage system and ultimately into the oceans — a problem these natural, biodegradable alternatives completely avoid.