"Neglected carbon buildup can also cause corrosion, especially if the residue contains corrosive compounds. Corrosion can eat away at the metal components of the firearm, compromising its structural integrity and potentially rendering it unsafe to use."
This statement is exactly my reasoning why I "think" I need to get the bore clean down to bare metal. I don't want to wake up from a 30 year coma and find all my guns look like my dads
I pulled out my fathers old Marlin 30-30 that was sitting in the Midwest in a gun case for untouched from mid 1980's to 2010. Amazingly there is no surface rust on the rifle. It was cleaned with a Foam Bore Cleaner (don't know which brand it was at the time but it was most likely one of the imported from Europe brands I was using from about the 1990/2000 area) until patches came out clean like the instructions on the can said.
This rifle will be a good test subject to see what is under the carbon and see what different products can do.