leave it in a airing cupboard/boiler room. for a few days and keep getting it out to make sure it has not shrunk to much try damping it with a sponge to help shrink it this may not work for you but...
Put a couple litres of warm water and a small amount of washing powder (couple thimbles full) into a sink. Keeping the brim out of the water, wash the back of the cap working your way forward toward...
Ebay or Amazon you can buy it from online uniform store -- i got my peaked cap last week from Anwar & Sons Pakistan and happy with the work..here you go to buy:...