For coolant, unless you can get good flood coolant, the next best option is air with a bit lubricant.

The key thing with nearly all machining, is to get chips away from the cutter. Getting chips away is even more critical with aluminium, as it can be very prone to chips welding to the cutter, which is never good and often fatal for the part, cutter of both.

I managed for a good few months machining aluminium with just WD40 and compressed air. I'd set the machine running, spray a bit WD40 on, hit cycle start, then wander back every couple minutes and blow chips of the part, and a little bit extra WD40 if it looked like things were getting too dry. I only used enough WD40 to give a light coating on the part/cutter to help stop chips sticking. If I knew there was a critical cut coming up I.e. spiral in, or deep slot, I'd stay and hold the air on the cutter to ensure no chips built up, and add in a bit extra WD40.
The WD40 does make the chips clump together more and a bit harder to blow away, but the trade off was they were less likely to weld to things.

I eventually made a mister, which removed the need for as much babysitting, but it would still need a bit extra assistance in deeper parts.