Oh, the magic of the soda bath.
I give you the same advice I practice in my own kitchen: Try never to give tin a hard abrasive scrub. Tin is a relatively soft metal and the amount of force you can apply with a scrub sponge and an abrasive cleaner (such as Comet, Bon Ami, Bar Keeper’s Friend, Soft Scrub, et cetera) is enough to abrade it away. It’s better to deglaze the pan while it’s still warm, or fill it with water and let it sit to soften food residue so it can be wiped away with a non-scratch scrub sponge.
But let’s face it, that might not enough to keep a daily-use pan clean. My skillets, in particular, pick up stubborn patches of hard baked-on food oils that won’t budge with normal cleaning. This seasoning isn’t necessarily a bad thing, but it’s a little unsightly.
My solution? A soda bath.
Please note that I mean sodium bicarbonate — NaHCO3 — which in the US we call “baking soda.”
The procedure is pretty simple: fill the pan with water to cover the discolored areas, add a large quantity of baking soda, and heat the water to a boil. Allow the water to boil for several minutes. Then very carefully drain the water — it is quite hot, after all — and give the interior a gentle-but-thorough scrub to remove the last vestiges of oils clinging to the tin. (Use a non-scratch sponge and a paste of baking soda and water as a gentle abrasive.) The result will not be as clean as a new tinning job, of course, but it will be much improved.
Here is a before and after for the skillet above. (Drag the slider side to side to compare.)
Here’s a second example — my beloved 24cm rondeau.
What’s happening here is that the baking soda makes the water very alkaline, which neutralizes the fatty acids in the food oils. Heat accelerates this chemical reaction and the food residue releases into the water. You’ll see the water turn brownish, with shreds of residue floating around.
Some caveats to keep in mind:
- Be careful with boiling water in an overfilled pan. You want the water level to cover all the discolored areas, right up to the rim if necessary so that the alkaline water can work on the residue. The baking soda will fizz and bubble quite a bit so be mindful of hot splashes.
- This is a messy process. The boiling water will fling hot soda particles all around your cooktop. Be prepared for some cleanup.
- It’s also smelly. The food oils will be fragrant, and it smells gross. Gird your loins.
- Be very careful moving the hot overfilled pan. Bail out of few cupfuls to drop the water level before you move it to the sink to dump it out.
- After you dump out the hot water and give the lining its final scrub-out, keep an eye on the rinse water. Brown rinse water is good — it means you’re removing the last stubborn remnants. Gray rinse water likely means you’re scrubbing into the tin itself and you should back off.
I like this technique for periodic cosmetic maintenance and I consider it only mildly invasive — the chemistry does most of the work so that the tin isn’t subjected to hard abrasive scrubbing. This is also a great first step to help you assess the lining of a pan you’ve bought. Old clean tin is usually a fairly neutral gray color; if you’ve bought an unrestored pan and the lining is brownish or greenish in tone, it may have long-neglected food residue on it that’s camouflaging the appearance of the tin. A good hot soda bath is a useful technique to reveal the tin beneath so you can assess its condition.