perhaps a useful tip from the numismatic world :
for gold and silver one can use specific cleaning chemicals which are free avalaible on the market, but for base metal one never use chemicals as it will have a huge negative impact to say the least.
Even for some silver Medieval, Roman or Greek coins chemicals can have a negative impact on the metal (discolouring, weakening the surface structure f.i.) and hence the value.
This is not so much the case ( value impact) with blades I would presume but nevertheless can result in unwated marks and stains.
A perfect alternative is vaseline: as it is not an agressive material at all, you gently with your fingers rub it over the dirty spot and leave it there for some time. This can be 15 minutes to an hour till even the next day.
Remove the vaseline with a cotton cloth and the dirt and or corrosion will come off.
If the required effect is not yet there, repeat it a couple of times and you'll see succes will be there at least.
It works for coins and I also used it on blades and metal scabbards.
Positive side effect is that a small layer of vaseline always remains which protect the metal against water, dirt, humidity and temperature.
Henceforth safeguarding your cold weapon.
Neverteless over time some dust might get onto the vaseline, so again clean it gently with a dry piece of cloth and add with your fingertip a small layer of vaseline.
An alternative or second solution :
in the numismatic world sometimes colourless nail polish is used for protection of zinc or iron coins: a tiny drop could be used on the former corrosive point / spot of a blade after cleaning to seal it as well as vaseline does. But then again it is up to you to decide if that "drop of polish" is acceptable on your weapon....
And if it doesn't come of or not completely, nothing can be done except an Elijah Craig to polish off the pain from your soul a little...
