Do I have to dry clean something that is dry clean only?

The reason it's dry clean only is because of the silk. Silk sucks in water & stretches out easily when wet. You really should get it dry cleaned, but if you absoluely can't afford to dry clean it, wash it by hand & lay it flat to dry. If you hang it from a hanger, the heavy amount of water in the silk will stretch it out & ruin it. Silk should never be put away dirty because sweat & deodorant can eat through it.