Here’s some information about the incorruptibles, that will be useful in addressing skeptics.
First off, incorruptibles are not mummified. Mummification was accomplished by removal of internal organs and the use of dry heat, usually desert sand. Incorruptibles for the most part, were buried in areas which were counter productive to the mummification process, some were buried in swamp land. Also, the bodies of other’s buried at the same site, and even sometimes almost the same grave, decayed, but the bodies of the Saints did not. Another point is that the clothing that incorruptibles were buried in, decays and has to be changed. St. Bernadette, was changed several times over the years since her body was last exhumed from the grave.
Second, the incorruptibles, unlike those in mummification, are not stiff and leathery. They are soft and supple. Some even still bleed. I believe it was St. John of the Cross, when they went to cut one of his fingers off, to be used as a relic, he began to bleed, so they left him alone. I could be wrong on whether this was John of the Cross however.
Some of the incorruptibles appear to have dark leather skin. This is usually the incorruptibles who died before the technology of glass coffins came into being. Their bodies where placed in chapels where the burning of candles over the years, cause the skin of the incorruptible to darken. Some are almost black. St. Bernadette and St. Catherine Laboure, were spared this because they were placed in a glass coffin. Also, their exposed skin areas are covered in a thin film of wax.
Skeptics will often point out that body of Lenin has not decayed. The difference here is that Lenin was never buried.
As soon as he died, a team of taxidermist went to work on him and his body is kept in a controlled environment, and must be reworked in the latest state of the art technologies for preservation. However, even here, his body has begun to decay a little.
The Saints, this never happened. They were buried after their death and most often, for decades, before they were exhumed and found to be incorrupt.
Anyway, you can get the full story with plenty of pics in the book, “The Incorruptibles: A Study of the Incorruption of the Bodies of Various Catholic Saints,” by Joan Caroll Cruz. She
did an excellent job researching the whole phenomena of incorruptibility.
Jim