I don't think it helps unless a coin is horribly terminally toned. They are out there, but I would not even try it with a valuable coin. I hate nasty toned coins, so I don't buy them to begin with. I don't know how the TPGs sleep at night grading them in UNC without details designations. There is a difference between attractive toning and environmentally degraded coins.
After action report These Morgans and Peace are some I inherited from an old collection from a long time ago. This was a varied assortment of toning and problems to try out. They were melt value before and are melt value now so there was little risk here. I got some E-Zest coin dip to see what it could do. In short, my assessment is that it can improve the look but does not work miracles. The lighter the tone is, the better the chance you have of improving the coin. The most improved was the 1922 Peace at the top left corner. It actually has cartwheel luster again. It has an original look to it and looks like some that get graded MS. Some had longer dips than others based on what I was trying to get removed. The reversed Peace dollar had a lot of black staining on the back and I over-dipped it for about 20 seconds to get it that good but can definitely can tell it's over dipped now. It's bright but no luster. It did remove most of the black staining but still not a great looking coin. The 1921 Morgan at the bottom had had an Acetone bath a long time ago. It wasn't too bad to begin with. I gave it five seconds and rinsed. It's ok but has a dipped, non-original look to it as expected. The Sterling silver shilling had very little change. The two dark Morgans in the middle, there was very little improvement from the dip. The 79 was a little better but nothing to get excited about.
Note to add, I rinsed them immediately in tap water then distilled water so no spots. Patted dry. To remove anymore would take a longer dip than recommended or a rotary tool which neither option is worth it.
Generally the high-quality coins with a short dip seem to do OK, but the more worn they are, the worse the results. I prefer a short dip at full-strength
I think you are correct. From my short experience with experimental dipping, it does nothing for circulated coins but making them duller. It does not help one bit. It might help UNC with ridding them with milk spots, but other than that or erasing unsightly nasty toning, it's useless. Period. That's my experience, your mileage may vary.
Yes I did. About 10 seconds, full strength right in the container. Very little change as pictured. I honestly was imagining MS surfaces as soon as a black coin touched the dip but that’s not how it goes. It’s not strong enough to do that anyway.
I bought a small jar of that 2 years ago. I don't recommend using that unless a coin is almost beyond help with terminal toning which is ugly AF. I learned this with personal experience.
I have dipped a lot of coins in my life. They were all going to PCGS for grading. Never had even one come back as cleaned. That show how picky I am. Most coins should not be messed with.
