I hate throwing stuff out, even pickle juice. I've found you can pickle onions in pickle juice very easily. Choose whatever type of pickles you like best - sweet, sour, dill, or bread & butter. SAVE the juice in the jar when they are gone, and make pickled onions. Usually I cook for just one, so I almost always have a partial onion that needs to be used. White, yellow, or purple onions work equally well.
1First, don't pour off the juice (brine) from that jar of your favorite pickles. They can be dills, sweet gherkins, even bread & butter pickles.
Slice onion thinly. I like half slices as they pack better. Pack onion down into the leftover pickle juice, being sure all the slices are covered with the juice.
2Replace lid and refrigerate for 2 weeks. Then use on hamburgers, hot dogs, salads, beans, or chop and add to relish or potato salad. The uses for these are endless.