At the dry cleaner's, when they starch clothes, does this clean them, or do they need to be washed first?

I've never used dry cleaning before and I'm a little confused. I dropped off 4 brand new dress shirts and asked for them to be cleaned. They said they usually just starch them. Should I wash them first, or does the starching process actually clean them?At the dry cleaner's, when they starch clothes, does this clean them, or do they need to be washed first?
~~Starch does not clean material. They should be laundering them first.~~At the dry cleaner's, when they starch clothes, does this clean them, or do they need to be washed first?
At the cleaners I work we can do it one of two ways: A. Spray starch on already clean clothes while pressing them. OR, B. We can use liquid starch when we wash them. The choice is up to you.
they wash them,starch them second..I am surprised someone still wants a starched shirt