There are many types of fruit jars. Glass jars rather than metal cans should be used for home canning. Jars should be constructed so that there is no contact of the fruit with metal, hence a jar having a glass cover is desirable. A large opening, simple construction, ease in cleaning, and perfect sealing are characteristics of good fruit jars.
Glass jars should be tested before using: Partly fill the jar with water, adjust the rubber and cover, seal, invert the jar. Examine carefully for leakage.