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[asdf12345]

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[Obsessed with Edges]

Depends on what exactly the discoloration is. If it's discolored by heat damage from grinding on a powered system, it may go deeper into the steel. If so, it could also indicate some damage to the temper (heat treat) of the discolored steel. If it comes off at all, it'd likely need more careful grinding and/or sanding to do it, as the damaged steel itself needs to be removed (may not be possible without severely altering the edge grind, if it goes deep).

Otherwise, most surface discoloration can usually be removed with some metal polish (Flitz, Simichrome, etc) and some scrubbing. The cleaned up area might appear a little 'brighter' afterward, but it should leave the original grind pattern intact.

Depending on what else it may be, other methods may be needed. Chemical etching can discolor the steel, and sanding/grinding is needed to fix that. If it's just glue or some other sticky, hard residue, then finding the right solvent might take it off (mineral spirits, acetone, etc.).

Might post a pic of the affected area, to get some more specific advice as to what it may be, and how to remove it.


David

 

[asdf12345]

Thanks for the advice. Here's a photo, let me know what you think.

 

[Obsessed with Edges]

View attachment 506611

Thanks for the advice. Here's a photo, let me know what you think.

Might try the metal polish first. That looks like it might just be some dirty stuff embedded in the grind marks; some coarser finishes really hold onto stuff like that. I see this on some of my own knives after stropping on a well-used aggressive strop (with a lot of black stuff on it); I have one blade with a bead-blast finish that really collects the dirty stuff from the strop. If you haven't already, you might just try wiping down the blade with a Windex-moistened towel or other clean cloth; this is how I clean mine, when I see that particular issue. If that doesn't take any of it off, then try the metal polish in a similar manner, maybe scrubbing with an old toothbrush or similar brush, before wiping it off.


David

 

[asdf12345]

Thank you! I'll try that.

 

[Rey HRH]

David,

would using cleanser like Comet or Ajax possibly work?

 

[Obsessed with Edges]

David,

would using cleanser like Comet or Ajax possibly work?

If it is just some dirty stuff, like swarf or polishing compound in the 'troughs' of the grind pattern, it should remove it. Most any household cleaner should handle it, like Comet/Ajax, Windex, IPA, etc. I suggested the metal polish, mainly because it'll work better if the the discoloration is more firmly affixed to the steel (like oxide, for example).


David