I think Marten has it exactly good bench vise (also great for stuck fixed cups) and brute force. Giving it a twist in both directions should pop it loose. On a Regina/Suntour type freewheel if the ears are damaged try to square them up again with Dremel or drill with drinding tip. Failing all that, remove cog portion of freewheel and grip whats left in vise.
BOB FREITAS
Who learned the cycle repair trade at
my Dads shop which started out as my Grandfathers Blacksmith shop
but most
recently in MILL VALLEY ,CA USA