Wondering if the new black you are seeing is a reaction to the metal that it was cut with? What did you use to remove the rotted flesh?

Tracy

Stainless steal knife

It may be a reaction to the stainless steel. But I would cut a little more to be sure. And don't use stainless steel if you can avoid it.

Ok I'll see the wound was tiny I cut out a whole areol

Corna cutting tool ( That can found at local pro type garden centers or area hardware stores ) and to the left is a soft stone. Use a proper tool to make cuts) use the soft stone to clean the (ummmm) stainless steel edges of the cutting tool when done, soak the soft stone in vinagar for a few hours now and then to clean it. It never hurts to quick clean the (ummm) stainless steel blades prior to use.

Just like your Chigargo( kitchen use) paring knife most common ( nearly every) steel cutting devices (blades) sold to the general public are made from carbon based steels. Your Chicargo knife ( For kitchen use a is a paring knife) Is the same high carbon hard forged stainless steel knife is the exact same steel as the cutter I use for my plants when needed.

From the kitchen to the garden I'm sure if it where worth the price for a better steel than stainless then I would have it . Simply advocating the RIGHT tool for the RIGHT job use your paring knife in the kithcn after the plant has had it's chance and then became a food.

See them scuffs on the left side of the cutter ? They're from letting Euphorbia sap to dry to long before cleaning.

Thanks nomen do you think the black game back because of the blade I can't go out for a new blade this week I do have a strong ceramic blade though.

Your very creative Spike. In my sincerest opinion your more creative than words can express.

The soft stone ( that I use to clean and sharping my plant care tools ONLY ) might prove difficult to find for many, may be harder to locacte than turface. Perhaps you look online ?

A duel sided hard stone easier to clean is used to sharpen and refine the edges of my cooking cutlery has a different surface that is intended for kithcen utility tools and knives.

Kitchen use tools aren't intended for plant plant knives aren't intended for kitchen use .

Suggestion dont over think it. Work smarter , not harder