Disclaimer: This information is offered with NO liability or responsibility on the part of PITCA.
The following information is either from our personal experience, gleaned from various conversations and meetings, or from reliable Internet sources. It's emphasized that heating a trivet can remove existing Enamel or loosen glitter. Also, vigorous cleaning techniques used on Cast Iron can scratch Brass. The preservation of patina is also a consideration when dealing with antique metalware. Be sure to read through the entire article first before proceeding.
Method #1: Glorifying Antique Polish The citrus and beeswax formula in this polish is designed for wood but it's also great for polishing and protecting the decorative cast iron you display. Just clean a trivet, apply polish, let sit for about 15 minutes, then wipe off and buff the to a beautiful shine. It's especially useful for cast iron trivets with enamel or japanning, finishes that could bake off if seasoned in a hot oven. Jim Ellwood (Trivets & Stands) recommends this polish and Lynn Rosack (The Expanded A-Z Guide To Collecting Trivets) also uses and loves it. WARNING: not to be used on cast iron used for cooking.
Method #2: Lower Heat You’ll notice a slight odor while the trivet bakes; open a window during this process.
1: Wash the trivet well in warm soapy water.
2: Scrub until the trivet is free of rust, using Bon Ami powder & a steel brush, steel wool or Brillo Pad.
3: Dry the trivet with paper towels.
4: Coat the trivet with vegetable oil and let sit for 15 minutes while you ...
5: Preheat the oven to 300 degrees F.
6: After 15 minutes, carefully wipe off all the oil with paper towels.
7: Bake the trivet on a rack in the oven for 1 hour.
8: Allow to cool on a baking rack.
Method #3: High Heat with Flaxseed Oil. From trivet collector Lynn Rosack: "I've never used this method, just recently having found this article; but the next time I have a trivet to season I'm going to try it and compare results with Method #1."
Wash the trivet well in warm soapy water. Clean until the trivet is free of dirt and grime, using a soft dental toothbrush, nylon brush or soft sponge. Dry the trivet with a cloth towel. Following the directions on the product, polish with a brass polish. There are special considerations when working with brass:
1. Advice from Antiques Roadshow:
“Wash your Bronzes! A finish is usually put on bronzes by an artist or at a foundry to give the metal a darker patina or to shade the metal to accentuate its three-dimensionality. Sometimes bronze is even coated with gold. That's why it's best to avoid polishing bronzes. Doing so is like vigorously scrubbing the surface of a masterpiece painting. In both cases, you're removing a layer of the piece that the artist intended to be there.
“Such damage diminishes both the integrity of your piece and its value. Ernest recently sold a bronze fountain by the American sculptor Harriet Whitney Frishmuth that had a value that would have dropped by $50,000 if the sellers had rubbed the patina off. Ernest and his co-workers simply washed the piece, which is recommended because bronzes don't corrode in water as do many other metals."
2. Advice from the Henry Ford Research Center:
“Historic cast bronze is usually 90% copper, 6% tin and 4% zinc. It has been widely used since antiquity for weapons, sculpture and decorative objects. Bronzes are traditionally patinated and usually appear anywhere from light green to dark brown. Patinas are sometimes described as any controlled corrosion that imparts an aesthetically pleasing color and/or texture to the artifact. Patinas may be applied with chemicals or may have accumulated over time naturally; in either case, owners should be aware of the potential value of these finishes.
“Cleaning - Stable or painted surfaces should be kept dust free. Vacuum-clean all stable artifacts regularly, using the nozzle attachment with a brush. A bristle brush or a toothbrush may help to raise dust from crevices.
“Polishing - Some, but not all, brass was traditionally polished to a bright finish, and altering original surfaces may reduce the historical value of an object. As mentioned above, some dark, stable surfaces may be considered "patinas". Collectors should be aware of any special finishes, especially lacquers and patinas, which may determine the correct color the metal should be, the degree to which it should be cleaned and/or the degree to which it should be polished. If you come across any special coating after you have cleaned off the simple dirt, you may wish to consult with a conservator before proceeding.
“If you wish to return a brass or bronze object to its original, polished appearance, it is usually possible with a fair amount of elbow grease and a good polishing compound.”