We've all seen the warning "dry clean only" on clothes tags, and it might as well be a legal document for all the respect we give it. But "dry clean only" isn't an unbreakable rule. What that tag really means is "don't put me in the washing machine."
Legally, manufacturers are required to notify consumers of just one method of cleaning clothes, and dry cleaning is always a safe bet. But the real issue with fabrics like silk and wool is that they shrink during the rough agitations of the wash cycle -- it's not water that does the damage.
Gently hand-washing delicates (as long as you know that the dye won't bleed) is nearly always an option. Be careful, though. Certain fabrics like suede and velvet should never, ever be washed at home. Better leave those for the pros.