Police have targeted schools across Sussex to try to reduce the amount of anti-social behaviour at Halloween.
More than 100 egg-throwing incidents were reported in the 24 hours from early on 31 October last year, along with 57 calls about fireworks misuse.
"Egg-throwing, at both property and people, has become a worrying trend," said Insp Richard Newman.
Kent Police are also urging parents and children to ensure the elderly do not feel vulnerable during the festivities.
"If children want to go trick or treating they should only call on people they know and who are expecting them," said Ch Insp Mark Harrison.
The force has given out 100,000 safety cards with advice on how to deal with trick-or-treaters and 80,000 leaflets aimed at 12 to 16-year-olds.
The message is also intended to ensure children are safe.
"Just because it's Halloween, we shouldn't encourage children to call on strangers or to walk around unsupervised in the dark," said Mr Harrison.
Sussex Police said they advised people wanting to celebrate Halloween to organise a party with friends or neighbours.
"We would also ask people to respect the wishes of anyone displaying the 'No Trick or Treat' poster by not calling at their home," said Mr Newman.