To clean a pewter flask, wash it with liquid soap and water, then rub it with a paste made from flour, vinegar and salt. This 90-minute process requires latex gloves, a sponge, white flour, vinegar, table salt, a bowl, a fork, soft cloths and a towel.Continue Reading
Remove the flask's cap. Wash the vessel with a soft sponge dipped in warm water mixed with a tiny dollop of liquid dish soap. Rinse the flask thoroughly, and pat it dry with a towel.
Put 1/2 cup of flour in a small bowl, then add 1 cup white vinegar and 1 teaspoon table salt. Mix the paste with a fork until no lumps remain.
Put on latex gloves. Dip a clean cloth into the flour paste, and rub it over the pewter. Use a circular buffing motion, and add more paste whenever necessary. After rubbing the entire flask, cover it with a thick layer of the cleaning paste, and leave the paste on for 30 minutes.
Saturate a clean cloth with warm water, and wipe off the paste. Blot the flask with a towel, then lay it on its side for about an hour. Leave the cap off until the interior is dry.