Assuming you are referring to the popular Miracle Maid cookware brand:
The best way to restore your Miracle Maid cookware is to use a product called Revere Ware Cleaner and Polish. This can be found at most hardware stores. You will also need a soft cloth or sponge.
To use, simply apply the cleaner to the cookware with the cloth or sponge and then buff it until you have achieved the desired shine.