What is the best way to sharpen scissors? ?

I have so many pairs of scissors that are dull and/or a minuscule amount of Stainless Steel is missing from a bad attempt at cutting wire - not fabric or paper. I am sure most of you have seen this type. Orange plastic handles and the kit includes everything from Jumbo size down to a pair that is about 4 inches in length. What is the secret to keeping these bad boys sharp? No name to them. Just a stamp that says made in Korea. Purchased at a hobby shop. Not a .99 cent store. They look like they are made of aluminum.