I wouldn't paint them bud. Just leave yours as they are. At least they haven't corroded being aluminium. If you paint them, it will flake off as soon as you tighten them and then they'll look proper tatty.
Mine being steel and having corroded I was literally going to stain the corroded area, but I'd probably have to keep on top of them.
EDIT: For example, these are the steel brackets from my Sustec strut brace brackets once I'd stripped all the paint off them...
And then after I'd treated the rust before powder-coating...
I'd be a bit neater when I come to doing my nuts and probably wipe them down before it dries completely, but you get the idea.