IEMusic
Headphoneus Supremus
Copper cables oxidizing and turning green (like copper roofs, Statue of Liberty, etc) is very common, especially with basic copper speaker wire. It’s not unexpected. Cheaper clear insulation yellowing, especially at the ear hooks, where they come in contact with a lot of sweat/secretions is also not unexpected. AFAIK, neither should really affect the sound significantly.
The Limpid Pro and LitzPS Pro are the same cable (I have both), and they both seem to be equally well constructed. The KBEar cables tend to be less expensive than the NiceHCK equivalents, but I’ve purchased NiceHCK cables at times for their 2 pin plugs that are designed for recessed sockets (the plugs have an extended rectangular part).
The Limpid Pro and LitzPS Pro are the same cable (I have both), and they both seem to be equally well constructed. The KBEar cables tend to be less expensive than the NiceHCK equivalents, but I’ve purchased NiceHCK cables at times for their 2 pin plugs that are designed for recessed sockets (the plugs have an extended rectangular part).