pinworms/threadworms

Can anyone help me. I'm trying to get rid of pinworms/threadworms by non-pharmaceutical means. Whatever I try seems to get them, but a day or so later, after I've stopped, they're back again. Presumably they hide in the mucoid plaque or small intestine. I've tried Black-Walnut Oil, oak bark enemas, Papayasan (something recommended in Dr Vogel's Nature Doctor book), and several health food shop anti-parasitic products.I've tried waiting for them to die off naturally and have followed advice about protecting against reinfection. My family don't have the symptoms but have been taking the pharmaceutical product.

I can't zap them - I've got to remove mercury fillings first and that's at least a yerr away. Besides these aren't supposed to be that difficult to get rid of compared to others.

Anyone else had similar problems?