Six high school students from Thessaloniki were charged yesterday with forging banknotes worth 1,100 euros to pay for their share of an upcoming school trip. The school principal was given some 4,000 euros by an 18-year-old pupil, which he had collected from his classmates to pay for the traditional five-day spring break. But the principal found that 15 bills had been forged. He called in police, who discovered that five other pupils, aged between 15 and 18, had been involved in forging the banknotes. According to officers, they used a scanner and printer to copy the bills and aluminum to look like the magnetic strip in banknotes. One of the pupils, aged 15, is thought to have forged money for classmates on other occasions. Officers also found forged blood donation certificates to justify absences from school at the boy’s home.