A Suffolk businessman handed police 570 knives in May after they were found in premises he bought.
A bladed weapons amnesty is under way in Suffolk and knife bins have been set up at Ipswich, Mildenhall, Lowestoft and Bury St Edmunds police stations.
Mobile bins are currently in place at Felixstowe and Newmarket.
Police said the businessman, who wishes to remain anonymous, was renovating premises and found the knives, which had previously been offered for sale.
In May, 885 knives were deposited anonymously in six bins around the county, taking the total since the campaign started last December to 3,829 bladed or sharp articles, police said.
Insp Sarsfield Donohue said: "The businessman had purchased a vacant business premises which he is renovating.
"In the stock room he discovered several boxes of knives, all believed to belong to a previous business and all which would have probably been offered for sale.
"Many were still in the original boxes and packaging.
"The new owner wanted to safely dispose of the knives and contacted the police station to discuss the matter."