Andy, I’m the designated “Mr. Chemistry” for removing spots/blots on the family fabrics…with generally excellent results. But when I was asked to remove a tan spot of unknown cause from a light/white wool sweater my wife had bought years ago in Ireland, things took a nasty turn because I didn’t know not to use bleach on wool…Yow!
Now (after gentle work, peroxide, a couple of tries with DiDi7, and a visit to the local dry cleaner, who ran it through twice) the spot is still just visible enough to ruin it as “good” clothing. What else should I try, or try again? We live in Chicago, so I should be able to find almost anyone/anything you suggest locally.
Failing that, is my fallback plan to dye the whole sweater light tan/brown a good one? We gotta take winter seriously here! Thanks! Conrad

Dear Conrad: I too, years ago, dreamed, while using my Gilbert Chemistry set, of becoming a scientist. The German language was the problem for me. I fear that the stain on the sweater is like a scar on the body. Always there, but in time may fade.
Since you live in Chicago, get over to Michigan Avenue, and buy your wife a new sweater.
Dyeing it will open the possibility of ruining it forever. Let her wear it when the mood strikes her. Like all old things, the older they are the better they get. Enjoy it for what it is, an old sweater.
Enjoy the coming winter and count your blessings that you are in the cold of Chicago, and not on the Gulf Coast of this great nation. Good Luck, Andy