Shirley sauce is a sauce found in some early 20th century American cookbooks. It appears to be a form of home-made ketchup.
SHIRLEY SAUCE
Source: The Modern Club Book of Recipes, c. 1921; pub. The John C. Winston Company
2 doz. large ripe tomatoes
4 cups vinegar
2 onions
3 tbsp. sugar
8 red peppers
1 tbsp. salt
Chop tomatoes, onions and peppers very fine.
Add vinegar, sugar and salt.
Boil for 3 hours.