When pristine white sneakers get scuffed or junior creates unwelcome wall art, consumers often turn to melamine sponges to remove unwanted marks. Sold by many brands—from Procter & Gamble to private label—these household cleaners have been on the market for two decades.

Authors of a new study shared in ACS’ Environmental Science & Technology contend melamine sponges potentially release more than a trillion microplastic fibers (MPF) per month on a worldwide basis.

The article  “Mechanochemical Formation of Poly(melamine-formaldehyde) Microplastic Fibers During Abrasion of Cleaning Sponges,” was published in early June.

The study authors are Yu Su, Baoshan Xing and Rong Ji.

Su, Xing, Ji and fellow researchers wanted to see how a melamine sponge’s density and the roughness of the surface it scrubs affect how quickly the foam breaks down. They also wanted to calculate how many microplastic fibers the sponge sheds.

According to the report, for the study, the team purchased several sponges from three popular brands.

Melamine cleaning sponges with different strut densities used against metal surfaces of different roughness were investigated using a reciprocating abrader.

The microplastic fibers formed were characterized in terms of their morphology, composition and quantity.

They were mainly composed of poly(melamine-formaldehyde) polymer with linear or branched fiber morphologies (10–405 μm in length), which were formed through deformation and fracture of the struts within open cells of the sponges, facilitated by friction-induced polymer decomposition, according to the study authors.

The rate and capability of microplastic fiber (MPF) production generally increased with increasing roughness of the metal surface and density of the struts, respectively. The sponge wear could release 6.5 million MPFs/g, which could suggest a global overall emission of 4.9 trillion MPFs due to sponge consumption.

The study, say authors, reveals an unrecognized source of the environmental MPF contamination.

To ascertain a rough estimate of how many fibers could be released per month, authors looked at Amazon’s monthly sales for August 2023, and with the assumption that the numbers stay consistent, the team calculated its number.

Author Recommendations

To help minimize the emission of microplastic fibers, the researchers recommend that manufactures create denser, tougher sponges that are more resistant to wear.

The authors acknowledged funding from the National Natural Science Foundation of China and the Key-Area Research and Development Program of Guangdong Province.

Sponge Market

P&G’s Magic Eraser, the highest profile option in the melamine sponge market, debuted in 2003.

By 2012, the company had manufactured more than 1 billion units of the sponge, as reported by Happi.

The range has expanded over the last two decades. The latest releases, rolled out in April 2024, include the Mr. Clean Magic Eraser Ultra Thick. It is 60% thicker than the original and has dual-sided chevron pattern to aid scrubbing.

The Ultra Thick version is said to be longest lasting eraser in the line, lasting 7x longer than the original Magic Eraser, according to P&G.

Mr. Clean has competitors in the category, including numerous options in private label as well as Amazon Basics and Scrub Daddy among others.