Use sand or pebbles. Some jars can be coated with glass paint to match colored bottles. 12 quart size jars are about Suggest different sizes. Small jelly jars are "quilted" creating a faceted glow from candle.
Light up your summer night with beach jar candle holders. A mismatched group of mason jars sits atop a table. Fill your jars with sand, add some mini shells and/or small beach pebbles, place a candle on top, then sit back and enjoy.