Nearly 30 people have been charged in a police crackdown on "money mules" who keep cash in their bank accounts for criminals.
The operation was initially into vishing fraud, where people are duped into revealing their bank details.
Detectives found that children were being recruited through social media sites to launder money for the gangs.
The 29 people charged are from Lanarkshire, Dunbartonshire, Ayrshire, West Lothian and Glasgow.
Police Scotland has now sent a warning to all schools in Scotland saying young people are increasingly being asked by fraudsters to receive and send money through their own accounts.
The children sometimes keep some of the money for themselves.
Parents and guardians are also being urged to be aware if a child suddenly has extra money or buys expensive new clothes or electronic gadgets.
A spokesman for Crown Office and the Procurator Fiscal Service (COPFS) said: "We been working closely with the police, other law enforcement agencies and the banks and we will take robust action against any person involved in money laundering where there is sufficient evidence to do so."