Pickled Shrimp and Peppers

2 pounds peeled shrimp
2 medium red onions, sliced into thin rings
1/2 cup cubed green bell pepper
1/2 cup cubed red bell pepper
1 1/2 cups vegetable oil
1 1/2½ cups white vinegar
1/2 cup sugar
1 1/2 teaspoons salt
1 1/2 teaspoons celery seed
4 whole cloves garlic
2 tablespoons capers with juice

Place shrimp in boiling, salted water and simmer 3 – 5 minutes until pink but still tender. Drain and rinse the shrimp. Alternate layers of shrimp, onion rings, and pepper in a sealable container. Combine the remaining ingredients and pour over the shrimp. Close the container and put in the refrigerator for 12 hours or more.