How can I best clean a small pewter vase?

If the vase is not an antigue one, it would be safe to use a homemade paste made from vinegar, flour, and salt. This has a mildly abrasive quality. If you have antique pewter, which is generally of a softer alloy than modern-day pewter, use more care. For older pewter, make a paste of wood ashes and water for polishing.