Stores across Bodmin, Wadebridge and Padstow have been inspected by police to ensure compliance with age restrictions.
As part of Operation Loki, a high-profile local police operation which is seeing more police visible on the streets of the Bodmin and Wadebridge policing area, retailers were tested to ensure compliance with age restrictions such as knives.
Police described the operation as a positive experience, with stores that failed the inspection educated by officers.
A spokesperson for Devon and Cornwall Police said: "As part of OP LOKI our Neighbourhood Team have been Test Purchasing knifes in Bodmin, Wadebridge and Padstow. The majority of stores complied with the Challenge 25 policy.
"Officers spoke to and educated any stores that didn't. Overall this was a positive experience.
"This will include proof of age checks for in-store sales, on collection or at the point of delivery.