[William P]

essentially, yeah, what did people use to, say, remove a lot of rust, or forging scale to make a piece pretty, to bring it up to the point you can start buffing it (i know that for russian and byzantine armies which is what i am researching this for, shiny gleaming helmets were the desired look)

i especially wish to know, partially to have the information to make a dshow of de-rusting/ finishing up a helmet for public crowds at a show late next month

i believe i remember someone, somewhere said pumice stones were involved but i dont know why

in place of anything else i might just use sand and oil rubbed into the surface with a rag, (i do know that oily sand was used for mail in the medieval period so maybe?

any help would be lovely.

[Ken Speed]

A metal polishing agent that has been used for centuries is horsetail fern which has a lot of silica in it.

[Richard Worthington]

Vinegar and sand for rust. Horsetail/scouring rush/Equisetum can be split and dried. Pumice, rottenstone, iron oxide (rouge), chalk...

[William P]

[Michele Allori]

I don't really know any sources, but vinegar is quite a good bet:
It was widely popular, easy to make, cheap, used for lots of stuff and known to be corrosive to some extent, I wouldn't be surprised if someone discovered its efficacy against rust in the middle ages

[M. Eversberg II]

You can mix various grits into an animal fat and it would act similar to a polishing paste. If that was done or not, I don't know, but it is doable with what they had.

M.

[Peter Messent]

You may want to look up strickles - a shaped wooden stick (the strickle) coated with tallow and sand. I've mostly heard of it used for sharpening scythes, but might be an option for weapons or armor as well. I imagine it would also work well with abrasives other than sand. In the case of plate armor/helmets though, I imagine a rag or piece of leather would work better just because it would conform to the curves better.

[Guillaume Vauthier]

I saw somewhere (I think that it was on Dimicator FB page) that they also could use brick powder and saliva to make a polishing paste, rubbed on the blade with a goat skin. Apparently it is quite effective.

[Richard Worthington]

I recall being told mail was cleaned by being tumbled with vinegar and sand. No source.

Equisetum is used around the world, and its use probably goes back to prehistory. That it can be split, dried, and stored, a Renaissance or Baroque source, I think.

The earth-abrasives like pumice, iron oxide, rottenstone, etc. possibly Cennini's Craftsman's Handbook, which is early Renaissance.

Brick dust is from 18th/19th century sources, as far as I remember.

Diderot mentions using dogfish skin as sandpaper.

I'll see if I can find more solid sources in the next few days.

[Mark Moore]

I don't know so much about vinegar and sand on mail. Seems like it would clump. I sold a rusty mail shirt to a fellow here once, and he put it in a burlap bag with fine, dry sand and then tumbled it. He said it worked perfectly. He never really elaborated as to *how* he tumbled it. I hope he didn't put it in the clothes dryer! I wouldn't want to be in the house with THAT going on! ....McM

[Dan Howard]

There is more than one source telling us that mail was cleaned by tumbling it in bran. It was possibly used because of the oils in the bran rather than ts abrasive qualities. Mail cleans perfectly well without any abrasive at all.

Native Australians used leaves from the Ficus coronata as sandpaper. They used sandstone lubricated with water as an abrasive.

[Richard Worthington]

I've seen bran mentioned in 18th/19th c. books, tumbled or rolled. I also came across a reference to wood ash on leather for cleaning knives. Also 19th. c.

Besides The Craftsman's Handbook (which wasn't published until the 19th c.), "how to" books don't show up often before the encyclopedists and the Industrial Revolution.

[Dan Howard]

Theophilus' On Divers Arts should qualify as a "how to" book similar to those written in the 18th/19th C. The Romans had plenty of these kinds of books as well. Pliny is the most well known.

[Richard Worthington]

Theophilus doesn't have much to say about cleaning rusty helmets.

[Dan Howard]

He specifically tells us that bran was used to clean iron. IIRC it is in the section on tinning.

[Richard Worthington]

You're right. I missed it.

[Richard Worthington]

Of course, he's describing polishing freshly tinned iron, not cleaning the iron. He says to clean it with a file, and not to touch the clean iron before tinning.

[Richard Worthington]

Musaeum Regalis Societatis 1681, p.315.

[Sean Manning]

[Peter Spätling]

you don't need oil when cleaning maille. Sand alone is a good abrasive.
Oil will just make your maille smell and sticky.
Armour was ground with sandstones (when available) and files of various grits. Afterwards the final polishing was probably done with "Polierrot" - polishing red - made from Wüstite. Using a mixture of water or oil the powder was applied to a leather strip which itself was mounted on a thick stick, or a leather covered water powered wooden wheel. (15th & 16th century)
I'm gonna find out more about this in the future....