Can only second these, really. One point on Sean’s suggestion above, though: “Servisol” is a brand-name - what you need is Contact Cleaner or Electronic Cleaning Solvent. The company makes other cleaning solutions and some of them are not suitable for use on electrical contacts. Farnell/CPC/RS-online will sell it mail-order.
Agree that the worst brand-name Apple cables are the ones Apple provides. Ikea, Belkin and anyone else with a name you’ve heard of will sell you a better quality cable.
For the USB-C sockets used on all recent Androids, modern iPads, and the latest iPhone, only pins are small enough to get in to the “moat” part of the socket, where the fluff likes to live.