Residents in Spalding are being urged to check charities are legitimate before donating.
Lincolnshire Trading Standards issued the warning after a leaflet drop asking for donations last week and said people should read any leaflets carefully.
Make sure the charity is actually specified and the contact details given are correct.
To report a bogus charity collector or a suspicious trader, please contact Trading Standards via the Citizens’ Advice Consumer Service on 08454 04 05 06.