I also wanted to suggest the spirit, but was scared of getting

no end. Seeing as Darren brought it up

A regular drop or two of spirit from a "mustard" bottle with a tiny hole in the spout does wonders for machining Aluminium.
Then I have a squirt-gun filled with the same type of synthetic oil & water mix Bogs mentioned for steel. A nice direct squirt on the work every-so-often works well. Normally this cutting oil is sold in large quantities only, but the one engineering firm here re bottles into 1 liter bottles. Still on my first liter bottle, and had it for 2 years now.
Lastly, I have a tin with a sweet-smelling cutting liquid that's made in South Africa; don't know what it is - but pretty darn expensive and will put you on a trip if you smell too much of it

. This I use for tapping, reaming, drilling deep holes, and sometimes for finishing cuts on steel & brass. Funny liquid this... I can make a dry finishing cut that's 1/2 thou oversize. If I try to re-cut, nothing comes off. Squirt of this cutting fluid on there, and it takes that 1/2 thou cut off perfectly.