How can I find super-warm secondhand mittens?

Channeling my ancient grandmother, I would think you might look for boiled wool. As I recall, sailors on oceangoing vessels wore boiled wool mitts, so dense they kept hands dry as well as warm. Boiled wool is fulled, if I’ve got that right; that fills out the knitted wool so that there are no spaces but rather an even, tight thickness.

Ebay has used boiled wool mittens.

Go to thrift stores, around here there are literally bins full of them.

What’s your price range? Why do you want 100% wool?

@snowberry Probably up to $20. Because I can afford to wait for a long time, I’m hoping to pounce on any good deals that pop up for effective but “non-sexy” gear.

I cannot recommend a wool mitten, but this is very close to what you are looking for, and it’s even in your price range new. The problem with wearing 100% wool gloves is that they can be itchy. I have some lovely wool things that are incredibly warm, but they are just so itchy I can’t wear them. A lining helps with that.

If you’re looking for affordable, very warm and non-sexy, I recommend wool finger mittens. This means you can wear them as gloves or mittens. New, the price ranges between $15—$26.

I have a pair, and they are indeed toasty in the nastiest, coldest weather. They are lined with Thinsulate. However because they are knitted, that means they are hand washable, which is an advantage in my opinion.

$19 finger mittens
https://www.amazon.com/Illinois-Glove-Company-Glomitt-Thinsulate/dp/B072BT4FGT/ref=asc_df_B072BT4FGT?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80814226275416&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584413751893052&psc=1

If you look long enough you might be able to find them used.

Second-hand thrift shops.

You can get mittens with warmable gel packs on Amazon. My mom likes them. After your hands are warmed up you can swap them for nice fluffy mittens.

You could join a “Buy Nothing” Facebook group for your city. You can ask in those groups for something you need. The group where I live is awesome.

You can layer using standard knit gloves and then mittens over. Having a glove layer right against your skin does a lot to help with keeping warm and the layer creates a warm pocket of air. Think of it like long underwear. The layer against your skin underneath another layer of clothing is significantly warmer than just having a regular shirt and another layer.

Plus, if you need to remove the mitten for dexterity you will still have a glove on.

I always bought gloves after the season for $10 every few years when I lived in cold places, but I did not usually live in below zero temperature places, and I rarely am out more than an hour, I don’t know your situation. That doesn’t help you right now, but in January you might be able to catch a really good sale.

I went to eBay and searched for sheepskin mittens. I found a pair of them. Remember, if you’re looking for genuine wool sheepskin, you’ll have to double check to make sure that it’s real leather with the sheepskin attached (not a pile fleece sewed to a leather back).
https://www.ebay.com/itm/274963202493?_trkparms=amclksrc%3DITM%26aid%3D1110018%26algo%3DHOMESPLICE.COMPLISTINGS%26ao%3D1%26asc%3D20210609144404%26meid%3D27a064bbf2fa4e7d939c4789be6ccfd3%26pid%3D101196%26rk%3D6%26rkt%3D12%26sd%3D203969302132%26itm%3D274963202493%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DPopularItemsWithSimpleRanker&_trksid=p2047675.c101196.m2219&amdata=cksum%3A27496320249327a064bbf2fa4e7d939c4789be6ccfd3%7Cenc%3AAQAHAAAA8A7MsZABwLuaVPSMs%252FTholPj6Yl%252BKviZkjBwf4Ot%252FuQXolzyf%252BLlVCLG6cWVGn%252FmxxyqB3CMcre%252BjlCgI0%252FrAmlyQ7VVH%252F0ypiydWV8RJgKyGa8mjZxednK4ML9MHV39mK9KNNJM0Pqh%252BCdEBRt7mj50RMjxTgOEs%252F60DmcDsuIpAUN%252Bn9Zoy%252F%252BBwmU0hp82pdb4IDo%252FHijY2OrEraB%252FBPSIwQuQPn9Xu%252Ft9J7wPmyU6ihMS5inCXs%252FY1PM92kM87xnT8yClKDXZNB7Gy6AM8WB5t0RMTlQ3DP4y8O16HZzvQ29Da5Y8hpv%252B%252BhnNXV36ZA%253D%253D%7Campid%3APL_CLK%7Cclp%3A2047675

Try a military surplus store.