1903 Blue Indian

Positive....someone told me once that there is a product called MS-70, or something like that, that leaves rainbow toning. I was wondering if acetone might remove it.

In real life it's super shiny and has a blue sheen. You can instantly tell its been altered. Still a good penny but altered nonetheless.

I think your lighting might be skewing the color a bit, the upper left corner has a significantly stronger blue tint than the other quadrants of cloth. The lower right areas that are more of an orange tone with hints of violet is fairly common on IHCs. As best I can tell, the "crackle effect" is just old toned fingerprints. MS70 is known for occasionally toning AU/MS copper in hues of blue and violet but those colors can develop naturally as well, albeit in a less vivid manner. The only way to remove the toning would be to dip the coin but then you would be left with a salmon pink IHC

Agree with Jbuck, try the acetone first, it won't hurt the coin at all if done properly and will most likely remove any AT without damage. Dipping copper and bronze coins in a silver tarnish remover usually makes the coins look horrendous afterwards.

Looks like it could have been a spray product called layout blue. It can be removed with acetone if that's what it is.

Pending on how much you like that coin, you could try several different methods to remove the toning.
Although there were 85,092,703 of those minted, that one is in relatively nice shape and cleaning may end up making it worth about $7 or more. About what you paid anyway.
First try the Acetone dip. Rinse with Distilled water. No effect? Then if you wanted to continue, standard Jewlery cleaners should work. At Walmart they carry several types. One is specifically for Copper. Of course now you would be up to about $5 for the Acetone, $1 for the Distilled water, about $7 for the Walmart Jewlery Cleaner. Purchasing one or more of the other types may prove to be more succesful but again, you would be adding about $7 each to the already expensive attempt to get rid of that toning.
Add in the massive cost of gasoline for a car to go to stores for those items will add even more money spent on that coin.
If none of the above work, then try Lemon Juice, Tomato Juice, Vinegar, battery acid, spit, dish soap, Lava Hand soap, my neighbors home made wine. Now if that toning continues, place on a large firecraker and light the wick.
To sum up a silly amount of cleaning methods above, I really suggest leaving that coin alone. The cost of removing that toning would cost more than the same coin in the same grade without the toning.

You do NOT need to rinse after using acetone. It evaporates completely without leaving a residue. The only thing rinsing will do is make the coin wet.

As using something like Ezest or the like on copper is NOT a good idea, acetone is definitely the way to go. IF it is one of the mentioned products, acetone likely will remove it.

Just go to Lowes or Home Depot or the like. They carry pure acetone in the paint section.

Be sure to use it outdoors with massive fans blowing, a Tyvek suit with butyl gloves, a respirator, goggles and at least foot long tongs. Otherwise you will be accused of not being safe.