You are welcome. The leftovers from tape is definitely "gunk". As far as what comes inside a new knife, that's less specific. Production knives generally come with a lubricating oil which may or may not contain preservatives and might be more focused on rust prevention than performance lubrication. Some have grease or a combination of grease and oil. Some have random dirt, yuck, or who knows what else from the factory, which can end up mixed into whatever oil or grease. I've even seen the odd metal shaving in cheap knives.
This is a big part of why I take apart every new knife that I can. Aside from inspecting or getting to know a new knife, I get to start fresh with known, non-toxic, fresh lubrication on clean internals. Different companies are different but for some production knives, doing this can make a significant difference in the action. In some cases, it's like fast-forwarding past the "break-in period".
While 75% alcohol will work, I prefer a higher concentration. (For what it's worth, isopropanol is better than ethanol for oils.) The higher the concentration, the better the solvent ability and the faster the evaporation.
