The only thing that boiling will do for you is to improve their appearance.

Strings become dead after a time because of a phenomenon called 'creep' that happens when you apply a load to metal. The strings gradually stretch until they will stretch no further. And that is why they sound dead. The improvement in tone comes from the recovery of a small amount of creep due to removing the tension from the strings. Most of the creep cannot be recovered and the strings soon stretch back to their old 'dead' position.

Replace 'em.

Bert.