New 30-cup urn has black-gold-blue stain after one use for tea water only; assuming hard water. Is the interior of the urn aluminum or stainless steel? Will vinegar solution remove the stain? Any suggestions to prevent having this reoccur with every use? Is aluminum or stainless steel interior best for hard water area?
Coffee Makers & Espresso... - Regal Ware - Coffee Urn Aluminum 30 Cup