Hotel amenity kits are quickly becoming the latest battleground for hotels looking to assert their green credentials.
Last week, Spanish hotel chain NH Hotels rolled out a new set of environmentally-friendly amenity bottles, which the firm says biodegrade faster than comparable products.
The new line, called "Agua de la Tierra", uses an additive called polyolefin which catalyzes the break-down of plastic in the bottle, reducing it to between two to seven years rather than 100 to a thousand.
NH Hotels owns 392 hotels in Europe and some 60,000 rooms, meaning that at least eleven million bottles will be produced - and giving travelers a sense of scale when it comes to the overall market.
Despite their notoriety as one of the least green aspects of today's hotels, the little bottles neatly arranged in the bathroom are expected by most travelers and are seen as a key differentiator and brand awareness tool by establishments.
For these reasons, few hotels have committed to ditching them altogether, although several big names - including Starwood's Aloft and certain Marriott and InterContinental properties - have made the switch to dispensers.
For the rest, finding a way to "green" the amenity kits may be the most preferable option.
In February, America's Best Value Inn and Canada's Best Value Inn became the first national hotel chain in North America to implement biodegradable bathroom amenities across all of its properties.
With NH Hotels now following suit in Europe, pressure is bound to increase on larger chains to begin stating what their bottles are made out of, as well as what is in them.
Others have come up with creative solutions, such as a hotel in Chicago which provides donut-shaped soaps, or the Global Soap Project, which sanitizes and redistributes used hotel soaps to refugee camps in Africa (citing 2.6 million bars of soap discarded in US hotels every day).