hi there,

I just pulled out my sword and noticed some dark brown spots on the blade. It is an old blade of the 1600's and is covered in black to grey patina and is still shiny. these spots look like stains and could only be a couple days old, i was wondering what could stain steel like this. I sometimes cut fruit and yesterday it got a little rain on it - but i always wipe it clean.

I tried to rub rub the spots off with a cloth then with steel wool and oil but they dont seem to move easily, as i say, they appear to be like stains on the steel - can anything in fruit or earth or rain stain steel like this? Any ideas what could've caused this?

cheers

Fruits, like the sweat of your hand or rain, earth (even some oils) etc., contain very aggressive acids which will stain most steels. If you really want to preserve an old blade keep it in a dry place and leave it alone as much as possible, unless an active rust appears on the blade.