Below is a list of Plastic Jars manufacturers from Leominster, Massachusetts. Plastic jars are small plastic containers that are used for storage or for the distribution of small quantities of products. They are similar to plastic bottles in that they are generally small, but a plastic jar is distinct from a plastic bottle because of its larger opening. This feature makes jars more practical than bottles in certain applications. Because of their small size and light but durable construction, plastic jars are an excellent material for storing and shipping food products.