If the loans are federally guaranteed and not subject to a statute of limitations, you can try to negotiate a reduced payoff and/or payment schedule, but the loans won't go away by themselves.
If they are not, and are subject to a statute of limitations, you can see if the lender lets the limitations period expire, or (as with guaranteed loans) try to negotiate a reduced payoff and/or payment schedule. (You should expect that entering such an agreement will reset the statute of limitations.)
Lenders do not have to agree to reduce the balance owed.

