West Yorkshire Police have warned that young people caught with flour or eggs over the Halloween period could face arrest.
The warning was issued as part of a drive to reduce anti-social behaviour in the region this Halloween.
The force issued an official poster for shops and businesses wanting to restrict the sale of flour and eggs this week.
The poster reads: "This shop is restricting the sale of flour and eggs as part of our commitment to reduce anti-social behaviour during Halloween.
"Any young person found in possession of flour, eggs and other items for an unlawful purpose may be arrested."