Faron Paul was so shocked at the knives that some teenagers were carrying that he decided to do something about it.
His Faz Amnesty campaign involves posting on social media, and asking for people to give any knives to him.
The knives are often swapped for vouchers, and he then hands them in to the police.
He spoke to Jayde Pearson about his campaign.
First Published 14.03.19: https://www.bbc.co.uk/news/video_and_audio/must_see/47557636/one-man-knife-amnesty-faron-paul-swaps-knives-for-vouchers