Originally Posted by
Bob Dopolina
Some lubes are very agressive and will push out any other lubes that may be on the chain. It's called 'wetting'. It will do exactly as you describe; It will leave your chain a black mess until all the lube and foreign particles are pushed out.
So, that means the grit on the chain was probably a combination of broken-down grease and wax, which came from the new chain and excess wax on the chainrings and derailleur pulleys. It sounded like sand or metal particles, but the wax I rubbed/wiped off was pretty crunchy. Totally plausible.