With the leatherworking example this article below provides details and source. Except for the asking a leatherworker bit which seems inaccurate. The scientists actually made new experimental copies of the tools to confirm what the bones were used for based on the wear to surfaces. https://www.theguardian.com/science/2013/aug/12/neanderthals-invented-tool-leather-lissoir.
They did note that
"Similar tools, called slickers or burnishers, are still in use by leather workers today, meaning the instruments may be the only known examples of modern tools that owe their existence to our ancient Neanderthal relatives.
“There’s a good case to be made for Neanderthals inventing this one aspect of modern human technology,” said Shannon McPherron at the Max Planck Institute for Evolutionary Anthropology in Leipzig. “It’s the first time we’ve seen Neanderthals use bone in a way that uses its unique properties.”
“These bone tools are identical in outline, profile, and use-wear to lissoirs. Lissoirs are known from the early Upper Paleolithic of western Europe including the Châtelperronian, Proto-Aurignacian and Aurignacian but are also found in the late Upper Paleolithic through to historic and modern time periods Lissoirs have a standardized shape and vary in size depending on the species used; they are an effective tool for producing and smoothly shifting pressure over a small area”
With the leatherworking example this article below provides details and source. Except for the asking a leatherworker bit which seems inaccurate. The scientists actually made new experimental copies of the tools to confirm what the bones were used for based on the wear to surfaces. https://www.theguardian.com/science/2013/aug/12/neanderthals-invented-tool-leather-lissoir. They did note that "Similar tools, called slickers or burnishers, are still in use by leather workers today, meaning the instruments may be the only known examples of modern tools that owe their existence to our ancient Neanderthal relatives.
“There’s a good case to be made for Neanderthals inventing this one aspect of modern human technology,” said Shannon McPherron at the Max Planck Institute for Evolutionary Anthropology in Leipzig. “It’s the first time we’ve seen Neanderthals use bone in a way that uses its unique properties.”
“These bone tools are identical in outline, profile, and use-wear to lissoirs. Lissoirs are known from the early Upper Paleolithic of western Europe including the Châtelperronian, Proto-Aurignacian and Aurignacian but are also found in the late Upper Paleolithic through to historic and modern time periods Lissoirs have a standardized shape and vary in size depending on the species used; they are an effective tool for producing and smoothly shifting pressure over a small area”