Steve E, I saw your post just after I got off my bike and realised that after all the rain riding recently my chain is pretty shocking! You definitely helped put me to shame ? I’ll go sort her out tomorrow....
ST.LL, A little bit of surface rust won’t hurt as long as there are no tight spots on the chain. Be careful with the wire brush - damage an O-ring and you will start to get tight spots and then you will have to replace the chain.