There's no denying the stench of aeroplane toilets.
With a steady flow of passengers paying a visit over several hours and no windows, the air in there can get pretty putrid.
But never fear, cabin crew have a nifty trick to keep the bad smells at bay.
If it's getting nasty in the loo, a crew member will brew a strong pot of coffee and take it with them when they clean the lav.
According to the crew from Norwegian Airlines, pouring a strong cup of black coffee down the toilet will neutralise odour.
Experts say coffee neutralises the bacteria causing the stink and brings a new, more welcomed smell.
Dr Alan Hirsch, a researcher from the Smell and Taste Research Center in Chicago, says the scent of beans is a neutraliser.
Many flight attendants also place coffee ground bags in bathrooms to neutralise the smell as it can absorb some of the odour.