Place a short, dry drinking glass in the center of a large glass bowl. Make sure the rim of the drinking glass is below the rim of the large glass bowl. Use a clear glass bowl and drinking glass if available.
Pour the vinegar into the bowl around the glass. Be careful not to splash vinegar into the drinking glass. Stretch a piece of clear plastic wrap over the bowl and the glass. Tape the plastic wrap securely to the sides of the bowl to form a tight seal.
Place a small weight, such as several quarters or a small stone, in the center of the plastic wrap directly over the empty drinking glass. Use enough weight to cause the plastic to bend downward slightly toward the glass. Place the container in a sunny spot for several hours.
Observe the container to make sure that the plastic wrap remains sealed over the glass bowl. Dry any condensation that forms on the outside of the glass bowl, and reapply tape as necessary to maintain the seal. Remove the plastic after several hours to recover the water that condensed on the plastic and dripped into the glass.