Dozens of discarded banana skins are being found littered across Ben Nevis.
The peelings, left by some of the 160,000 visitors to Britain's highest mountain, can take as long as two years to degrade.
A litter pick over two days last week by a Richard Pyne of mountain clean-up campaign the Real3Peaks Challenge collected 8kg of banana skins.
The John Muir Trust, which manages visitor impact on Ben Nevis, has tried to tackle the problem for years.
In September 2009, the landscape conservation charity removed 1,000 banana skins from the summit during a clean-up of litter.
The Real3Peaks Challenge, which also organises litter picks on other Scottish mountains and Scafell Pike in England and Snowdon in Wales, has taken away as much as 230kg of rubbish from Ben Nevis in a previous litter pick.
Last year, the amount was down to 135kg but most of it was banana and other fruit peelings as well as tissues.
How long does litter take to degrade?
- Banana skins/orange peels - two years
- Cigarette butts - 12 years
- Plastic carrier bags - 10 to 1,000 years
- Plastic bottles - 500 years
- Crisp packets - 80 years
- Tissues - A month
Sources: Zero Waste Scotland/Recycle It 4U
The John Muir Trust said the popularity of Ben Nevis, like other parts of the Highlands, had "surged" with visitor numbers to the mountain up from 120,000 to 160,000 last year, plus 300,000 in Glen Nevis.
Ben Nevis land manager Alison Austin said: "We welcome the rising public interest in Scotland's mountains but such huge numbers of people concentrated into a small area does have a serious impact on the mountain, from footpath erosion to litter.
"We know that more experienced hillwalkers understand they should leave nothing behind but their boot prints.
"But more casual visitors to the hills are less likely to be aware of the fact, for example, that banana skins can take up to two years to degrade, which is not just unsightly but can also damage the mountain's fragile ecosystem."
The trust said wildlife was eating the discarded bananas and skins and the sugars in the fruit risked the animals' health.
Ms Austin added: "So our message to visitors is enjoy the mountain and good luck in your endeavour to reach the top - but leave no trace behind."
Mountaineering Scotland, which runs a litter campaign called #TakItHame, said: "Ben Nevis has particular problems with litter of all sorts because it's so popular, and because so many of those who climb it aren't regular hill-goers and don't seem to appreciate the harm they are doing by leaving litter, whether it's plastic or banana peels.
"We urge everyone to avoid dropping any litter and, indeed, to pick up any they find."