I'm fairly new to this, but I used an ultrasonic cleaner with hot water and a little liquid dishwasher detergent. It worked like a charm. For items too big for the ultrasonic cleaner, a good cleaner (a nondescript product I bought at the 99-cent store) and brushes to suit worked well. I tried to minimize contact between caustic cleaners and aluminum, but sometimes it was unavoidable. When nothing else worked, I used whatever was necessary, but rinsed it off quickly and thoroughly. I've done a few bikes now, and a lot of it is technique and not chemicals. Practice makes perfect.