Posters discouraging Halloween callers are being distributed to the elderly and vulnerable people in Cornwall.
Police said they have been working with Cornwall Council to ensure people felt safe in their homes.
As well as the "No Trick, No Treat, No Thanks" posters, people are being offered advice on dealing with with trick or treaters and bogus callers.
Community officers have also been visiting local schools to encourage young people to behave responsibly.
Cornwall Council said: "We are not trying to spoil the fun of Halloween but we would like trick or treaters to recognise that some people, particularly if elderly or vulnerable, might be distressed by strangers knocking at their door during the evening."
Devon and Cornwall Police said there would be high visibility patrols taking place over Halloween.