Place fresh or dried citrus peels into a glass jar that can be lidded, e.g. a canning jar.
Cover the peels with white vinegar. Shake a bit to cover the top-most peels entirely with vinegar.
Cover and allow to sit for at least a week, up to four weeks.
Strain out peels and return the vinegar to the jar. Use as needed.
Notes
Peels can be composted or use to brighten stainless steel sinks, scrub toilets or shine copper kitchen tools. A select few may be ground in your garbage disposal to clean it. The peels will be very soft, FYI.