Just spent all evening making a 150mm cut across a 6mm sheet of aluminium. Not fun I can tell you. I used a jig saw and got through three HSS blades. After the first blade I tried using paraffin as a lubricant and it made a big improvement. Holding the saw for about an hour and a half on and off was horrendous because of the the vibration. It was all the more annoying because I paid over the odds on eBay to get a piece exactly the right size but the description changed during the auction. There was even a line already marked where I had to cut it.
Ironically, after finding it so hard to saw, I managed to clean up the edges on my bench sander demonstrating how soft aluminium is. I probably needed a saw with coarser teeth. Perhaps I should have tried a wood blade but I think that would have been too coarse.
Drilling next: I hope that goes a bit better. I will definitely use paraffin again. I am not sure where I got that tip from, it might have been my Dad.
PS: Found a better way of blogging my pictures so now you can click on them for a higher res version. If anybody wants to see a better version of a previously posted image let me know and I will upgrade it.