Thankfully no permanent discoloration and I discontinued usage of the Windex when I was able to realize it's inefficiency. Good thing too because I'm preserving blades worth upwards of 10 grand. It was recommended to me by an American polisher as substitute for Uchiko. It will strip the blade bare naked of any oil, but it leaves streaks of blurriness or color that makes the blade difficult to see in lighting than with the oil.
Standard Uchiko from Japan is crap and should never be used on Hadori polish. Polisher Uchiko is better quality, but still, I would not use it on Hadori polish. It is good for Sashikomi polish. But very few blades are ever polished in 'true' sashikomi. The blade you think is sashikomi polish is, in all actuality, most likely a mix between hadori and sashikomi or sashikomi with a touch of acid.
Fujishiro Uchiko I was told is not actually real Uchiko. Because Uchiko is bad for a modern polish, Fujishiro Uchiko is supposed to be only part Uchiko and a mixture of other things that's similar to Uchiko which minimizes scratching of the blade and preserves the polish. I don't know what that mixture is supposed to be.
Standard choji oil from Japan is, in my opinion, also crap because it will leave a slight residue on the blade and does not evenly disperse. Machine oil is good or sewing oil. I'm not completely sure what Fujishiro oil is supposed to be comprised of, but I was told by other Japanese collectors that it is superior to everything they've used for Nihontou in particular.