So I’ll admit I didn’t take such great care of a couple glasses when I first got into this hobby. Despite using a warm water/white vinegar bath, or doing vinegar + baking soda, I can’t get the small stains in the bottom of the bowl out. Anything else I could try?
Put some ice cubes in the glass, pour in a a table spoon or so of salt, swirl around, then rinse out. The salt granules help the scouring without scratching
The bottom line is - you need something high pH to get the stains out, just like we use in wineries, and then something acidic to rinse so it’s “squeaky” clean. I use a bit of peroxy carb (high pH winery cleaner) in my worst glasses and decanters from time to time. I have some citric acid powder to take care of the rinse, but in a pinch I use…wine, preferably white just so we’re not restaining. Use a small amount, tip and twirl the glass to coat the inside, then water rinse for squeaky clean.
And yes, I’ll usually let the high pH solution sit in the glass for a while if not overnight to get rid of bad stains.
Because I don’t think anyone’s said it, even if you don’t clean your wine glasses the night you use them, rinse out the spot of wine at the bottom before going to bed and/or leave some water in the glass overnight just so things don’t dry out before you get to cleaning.
Or I suppose you can do the old bachelor underpants thing. When you need them clean - buy new ones.