Three Bean Salad

1 can French-style green beans
1 can drained yellow wax beans
1 can red kidney beans
1 cup finely sliced celery
4 to 6 scallions, sliced (including tops)
3/4 cup vinegar
1/2 cup granulated sugar
1/2 cup oil

Drain green beans and wax beans well. Barely drain kidney beans. Place beans, along with celery and scallions, in a large bowl and marinate at least overnight with vinegar, sugar and oil.