It is the lot of many students to wait on tables to make ends meet. But a team of Plymouth University divers found themselves in the murky waters of the city's Sutton Harbour after a waterfront cafe challenged them to collect mugs condemned to the deep by diners.
In one afternoon, the students recovered 200 from the silt where some had lain for decades. A few of the mugs were encrusted with barnacles, while others had been pitched into the water in recent weeks.
Georgina Curtin, the owner of Cap'n Jaspers, admitted she was shocked at the haul. "We suspected that some mugs had been thrown over, but not quite the quantity they came up with."
The students are studying for a professional scuba-diving qualification at Plymouth's Diving and Sailing Centre as part of degree courses ranging from marine biology to civil engineering.
Some £40 was raised for charity.