Experts hoped the tool would provide clues to the final resting place of victim Keith Bennett, whose mother Winnie Johnson died last month without knowing what became of his remains.
The 12-year-old was abducted and murdered by Ian Brady and Myra Hindley in 1964 and is the only one of the five young victims whose body has never been traced.
But Steve Kershaw, senior lecturer in forensic analytical science at Manchester Metropolitan University, who has been examining the spade, said he has been unable to trace its history.
He said: "It is very, very corroded. The metal in it appears to be a reasonable steel that pre-dates the start of recycling. There was some vegetation attached to it and was found in an area of peat. The handle had been broken off, but even if we had lots more time, and even if we had established that it was a spade from the 60s or pre-dated the 60s, we would not have necessarily established if it was anything to do with Ian Brady.
"The only way we would have been able to tell is if it had DNA on it and that is harder to tell with the handle gone, with it being so corroded. Although some vegetation has survived, there is very little chance of DNA having survived."
He said the spade has now been returned to its finders, members of Worsley Paranormal Group, who had been searching the area for signs of where Keith's remains lie on the moor outside Manchester.
Brady, 74, who remains in prison after being locked up for life, had been urged by police to "at last do the decent thing" and finally tell Keith's family where he buried him on Saddleworth Moor so he can be given a Christian burial.
Keith's brother Alan, who was nine when his brother was taken off the street by Brady and the late Hindley, said Keith would remain in the "possession" of his killers until his body is found.
Writing on his website Mr Bennett said: "As far as I am concerned, until Keith is found then he is still in the possession of Brady and Hindley.
"Our fear as a family is that now my mother is no longer with us, this may be seen by the police and the media as some sort of closure to the case.
"This must not be allowed to happen both out of respect for Keith and my mother's memory and for those of us who loved them both."
The family's solicitor, John Ainley, said of the spade: "As far as I was concerned it was going to be subject to forensic tests and until we know whether or not it is relevant there is no comment from me or the family. We are keeping an open mind until the results of the tests are revealed."
A spokesman for Greater Manchester Police said it did not have any information about the spade.
