This is a stainless steel(?) machete that is practically mine. No markings of any kind are visible, and it was trash picked, so no info about it is known.
But the first step in making a patina with Alka-Seltzer is to get some Alka-Seltzer and grind it into a fine powder. Next, rub the area of the steel that you want to discolor with a green Scotch Brite pad. Fire up a vaporizer and you are ready to begin.
First, move the area you will be working on back and forth over the steam, but only enough to get a small coating of water.
Second, grab a pinch of Alka-Seltzer powder and sprinkle it onto the wetish blade. Be careful not to pile it on in one spot.
Now, let the steam soak the Alka-Seltzer so that it is sure to stay on the blade by putting it over the steam on an angle.
Let the steam really condense on the blade, so that it is running a little. Then let the blade sit with the Alka-Seltzer side up for a minute or two, so that the Alka-seltzer is not longer distinguishable from the water.
Then wipe the Alka-Seltzer water off and admire you results.
NOTE: The water that was on the blade after I let it soak was noticeably dirty, and this may have helped make the patina (the dirtiness of the blade, that is) so don't clean your blade before doing this.