Some folks swear by fancy soaps. I just use Ivory Snow or Woolite. Depending on it's age, the soaps available when it was made was probably harsher than some we have now, but always better to err on the side of caution. I know some who will add vinegar to the rinse water, too - to neutralize any remaining lye from the soap and stabilize dyes.
Can you tell from the fabrics what era they date from?