I tried doing a forum search but I could not narrow my terms specifically enough and didn't have the time to go through 25 pages. Sorry if this is a repeat, but I couldn't find anything on it.

How would a sword be cared for back in the day? Would it have evolved at allover time from the roman barbarians to the renaissance fencer? I'm sure they would have not let the sword rust, but to do this some sort of oil would be needed as well as some way to polish out rust. Any clues into historical sword care, myArmoury?

There may be a mention or two of this in the works of Francis Gies, Richard Barber, David Crouch, etc. As a trainee (squire, man at arms) they would have received some practice. Sand or fine pumice could plausibly have be used for polishing, and a small stone for sharpening. A variety of oils existed in that time (whale, linseed, animal fats, etc.), and could have been applied periodically by the sword owner. Descriptions of tournament, siege's, and campaigns described in some of the above authors' texts on the period state that there were small camps of blacksmiths, armourers, saddlers, etc. that traveled with armies. I suspect that these would have handled anything more serious than routine preservation and oiling.

Here's some previous discussion on the subject:

http://www.myArmoury.com/talk/viewtopic.php?t=7223

I know there's been more discussion on the subject than that, but I haven't hit the right combination of search terms to find them....

I cannot recall the resource, but it seems that I read or heard somewhere that animal fat was boiled down and sand/pumice was mixed with it to make small 'cakes' that each soldier could carry with them for maintaining armor and weapons during the later Roman Republic.