Combine vinegar and 1 cup water; soak sweetbreads in mixture for 15 minutes.
Remove membranes; separate sweetbreads.
Combine crumbs and flour.
Dip sweetbreads in egg; roll in crumb mixture.
Sprinkle with salt and pepper.
Heat small amount of salad oil in frying pan; saute sweetbreads until brown.
Cover; cook for 30 to 40 minutes.
Serve with Worcestershire sauce, if desired.