How to clean antique brass

[crest]

I've got an antique brass lampbase from Laura Ashley and it's developing some bluey-green spots. Does anyone know what I should use to clean it?

I'm too worried to try Brasso in case it turns it too new and shiny instead of staying antiqued. That's the problem, you see.

Lakeland do this lemon oil impregnated cloth that l've used on my brass letterbox (100 years plus old) which brought it up a treat when brasso was useless.

That sounds like a good idea there's a Lakeland near where I live and so I could get some.