Seed the peppers and chop fine with the onion. Put into a bowl, cover with boiling water and let stand for 5 minutes. Drain and cover again with boiling water, let stand for 10 minutes longer. Place in colander or cheesecloth bag let drain over night. In the morning add the vinegar, sugar and salt. Boil for 20 minutes. Place in hot sterilized jars and seal.