Shot a lot of old ammo and a good bit with the green funk- we always used a puff of bronze wool to clean it.
Fine Grade Bronze wool is very useful-

Try loading it as is if it chambers and functions just shoot it up without any cleaning.

The old phrase if it fits it ships

I have shot a huge amount of shaggy looking old ammo without issues.

Oldest I have shot was made prior to World War One and all went off with no drama at all