Mark Joiner was roused from his cell earlier than usual on June 24, 2012.

He was handed a bottle of Clorox and was told it was clean-up time.

Joiner was used to cleaning up cells in Dade Correctional Institution’s psychiatric ward, and many of them were frequently brimming with feces and urine, insect-infested food and other filth.

Joiner thought he pretty much had seen it all, from guards nearly starving prisoners to death, to taunting and beating them unconscious while handcuffed for sport. He recalls one inmate was paid a pack of cigarettes to attack one sick inmate whose only offense was to ask if their mail could be delivered before bedtime.

But Joiner, a 46-year-old convicted killer, saw something that morning that shook even him to his core.

On the floor of a small shower stall he was ordered to clean, he saw a single blue canvas shoe and what he later realized was large chunks of human skin.

The skin belonged to Darren Rainey, a 50-year-old mentally-ill prisoner whom the guards had handcuffed and locked in the cell the night before. Witnesses and DOC reports indicate Rainey was left in the scalding hot water for hours, allegedly as punishment for defecating in his cell.

Joiner, in an interview with the Miami Herald on Tuesday at Columbia Correctional Institution in Lake City, said he could hear Rainey screaming as hot steam filled the unit that night. He also heard the guards taunting Rainey, saying “How do you like your shower?’’

But the officers, many of them over six-feet tall and over 250 pounds, had done it before, Joiner said. The shower was just one tool the corrections officers used to torment prisoners in the ward, known as the transitional care unit.

The man’s name was Robert Taylor. And according to this inside source with more than 10 years of employment at the jail, Taylor was a recurring inmate; he was also an alcoholic.

“I was there when Taylor came in,” the source said. “And he looked really bad. A couple of us told the medical staff that he needed to go to the hospital because he was detoxing.”

But according to the source, Taylor was not taken to the hospital because two officers were required to escort him there, which would have weakened the manpower inside the jail. Moreover, the source said, sending corrections officers to watch an inmate at the hospital costs more money. There is a clinic inside Burlington County Jail, the source said, but an officer is required to watch inmates in there as well.

“We try real hard not to put anyone in the clinic if we don’t have to because it takes a C.O. off the floor,” the source said.

So, Taylor was placed in segregation, where he laid on the floor for five days without ever eating a single bite of food or taking a single shower, according to two different sources who were there at various times.