They were able to remove a good portion of the paint but a 'shadow' remained visible which is not unusual if you don't have the right materials.

The surface had a few bare bronze spots, but was mostly covered in an original dark brown patina and green verdigris.  

Verdigris can be the result of oxidation of the copper alloy within the bronze after decades of outdoor weathering. It can also be applied like paint to a bronze surface. I speculate, given the drip marks that are highly unlikely to be caused by weathering, that this particular verdigris is a chemical application. However, I also find it unlikely that the artist would approve of the unsightly drips and streaks. So, I believe that this was not the artist’s doing but rather applied sometime after the artist’s death (1941) and before it was gifted to the museum (1947) by the previous owner of the sculpture. My theory is supported by the fact that during the 40's applied verdigris was a popular choice.

The Story

The number 38 spray-painted across Lincoln's chest refers to the largest one-day mass execution in American history known as the 'Dakota 38'. The story begins with the American Indian Wars which is a catch-all phrase for all the conflicts between Native Americans and the US Cavalry which spanned more than 300 years. Until Lincoln became president no prisoners were ever taken. If a conflict arose between settlers and Indians and the Cavalry intervened, the results were invariably a massacre of an entire village including women and children. The Indians rarely won. When Lincoln became president he established 'due process' so that prisoners had to be proven guilty to be executed. Here is the story of the 'Dakota 38':

On September 28, 1862, two days after the surrender at Camp Release, a commission of military officers established by Henry Sibley began trying Dakota men accused of participating in the war. Several weeks later the trials were moved to the Lower Agency, where they were held in one of the only buildings left standing, trader François LaBathe’s summer kitchen.

As weeks passed, cases were handled with increasing speed. On November 5, the commission completed its work. 392 prisoners were tried, 303 were sentenced to death, and 16 were given prison terms.

President Lincoln and government lawyers then reviewed the trial transcripts of all 303 men. As Lincoln would later explain to the U.S. Senate:

"Anxious to not act with so much clemency as to encourage another outbreak on one hand, nor with so much severity as to be real cruelty on the other, I ordered a careful examination of the records of the trials to be made, in view of first ordering the execution of such as had been proved guilty of violating females."

When only two men were found guilty of rape, Lincoln expanded the criteria to include those who had participated in “massacres” of civilians rather than just “battles.” He then made his final decision, and forwarded a list of 39 names to Sibley.

At 10:00 am on December 26, 38 Dakota prisoners were led to a scaffold specially constructed for their execution. One had been given a reprieve at the last minute. An estimated 4,000 spectators crammed the streets of Mankato and surrounding land. Col. Stephen Miller, charged with keeping the peace in the days leading up to the hangings, declared martial law and banned the sale and consumption of alcohol within a ten-mile radius of the town.

As the men took their assigned places on the scaffold, they sang a Dakota song as white muslin coverings were pulled over their faces. Drumbeats signaled the start of the execution. The men grasped each others’ hands. With a single blow from an ax, the rope that held the platform was cut. Capt. William Duley, who had lost several members of his family in the attack on the Lake Shetek settlement, cut the rope.

After dangling from the scaffold for a half hour, the men’s bodies were cut down and hauled to a shallow mass grave on a sandbar between Mankato’s main street and the Minnesota River. Before morning, most of the bodies had been dug up and taken by physicians for use as medical cadavers.

Following the mass execution on December 26, it was discovered that two men had been mistakenly hanged. Wicaƞḣpi Wastedaƞpi (We-chank-wash-ta-don-pee), who went by the common name of Caske (meaning first-born son), reportedly stepped forward when the name “Caske” was called, and was then separated for execution from the other prisoners. The other, Wasicuƞ, was a young white man who had been adopted by the Dakota at an early age. Wasicuƞ had been acquitted.

Letter from Hdainyanka to Chief Wabasha written shortly before his execution: "You have deceived me. You told me that if we followed the advice of General Sibley, and gave ourselves up to the whites, all would be well; no innocent man would be injured. I have not killed, wounded or injured a white man, or any white persons. I have not participated in the plunder of their property; and yet to-day I am set apart for execution, and must die in a few days, while men who are guilty will remain in prison. My wife is your daughter, my children are your grandchildren. I leave them all in your care and under your protection. Do not let them suffer; and when my children are grown up, let them know that their father died because he followed the advice of his chief, and without having the blood of a white man to answer for to the Great Spirit." (excerpt from usdakotawar.org)

Depending on how you look at it, Lincoln either saved 265 native people from execution or sent 38 to their deaths. This blood-red graffiti across Lincoln's chest, hands, and face is clearly bringing attention to the 38 deaths, here in a region of Vermont with a sizeable population of 'First People' and college students.

Or is it!? Another interpretation is that the spray-painted number is 88, not 38. In the dark annals of the White Supremacists, 88 is a code for the 8th letter of the alphabet forming HH, Heil Hitler. And Lincoln is their arch enemy having freed the slaves. and this area of Vermont has a share of these characters as well.

Bronze Disease

Bronze disease is corrosion of the copper alloy in the bronze below the patina cause by chloride which is an environmental pollutant. This pollutant is particularly concentrated in the air where roads and walkways are salted. It is also one of the compounds found in acid rain. This corrosion will continue to spread if it is not removed.

Bronze disease is not often found on bronze sculpture, but this Lincoln had several dozen small spots, beside the left eye, under the rim of the hat, in both ears, and on the back of the neck. The spots varied in size from an inch in diameter to a pinhead. 

Using sculpting tools, the blooms of chloride corrosion were picked away without scratching the surrounding patina. Remaining residue was brushed off using rigid plastic brushes on a Dremel. The surface was cleaned with xylene, a solvent which removes dirt and oxidation without harming verdigris or patina. These areas were coated several times with Everbrite. This polymer coating filled and sealed the small pits and cracks at the root of this ‘disease’, preventing further outbreaks. The coating will last 5-10 years, depending on weather conditions. I guarantee it for 5.

The image on the left shows the disease. The right shows blooms and residue removed.