Credo Corn Ex Credo-Ex features interchangeable blades one large and one small for premium corn removal. Corn-Ex is very easy to use: Please put the opening of Corn-Ex on the corn and remove it with slight pressure. Due to an extremely sharp blade, Cron-Ex stops the pain within seconds safely and without any chemical means. Corn-Ex comes with two sizes of blade: Small one for corns on the toes (hammertoes) Large one for corns on balls and soles