I had been buying your everyday synthetic nylon sponge for years and hadn't given it a second thought until I realized that a yellow dye filled my kitchen sink every time I used it. Seeing that dye made me wonder if there was a cleaner alternative.
There was! The above product Twist is a natural unbleached loofah sponge, free from dyes and chemicals - and it's completely biodegradable! Surprisingly, they also hold up much better than the petroleum based sponges. In fact, not one of mine has fallen apart despite frequent runs through the dishwasher.
An added bonus is that they're also a lot more attractive to look at!