Scrap metal dealers in South Yorkshire and North Derbyshire are being warned to adhere to new licensing rules.
Legislation means anybody collecting scrap metal or salvaging motor parts must have a licence issued by their local authority.
Traders must keep records for three years to show who they bought metal from, while cash payments for scrap are now banned.
Bolsover Council and North East Derbyshire Council are both promoting the new legislation.
Coun Dennis Kelly, Bolsover Council cabinet member for the environment, said: “The rules mean those collecting scrap metal or salvaging old vehicles are properly licensed and regulated, meaning we can make sure only suitable and reputable services operate locally.”
Coun Nick Foster, North East Derbyshire Council environment spokesman, said: “People should be aware traders are required to verify the names and addresses of customers now the new rules have come into force.”