[gsxrken]

All of the 15a receptacle circuits in our house built in 1967 were aluminum. I replaced all of them by cutting a small 4x4 box in the Sheetrock above each receptacle, and undoing the staple that was holding the wire to the framing stud. Then I would cut the aluminum wire just above the box and temporarily attach new copper wire to it, and go to the next box in the circuit, cut the hole, pull the staple, and now I could pull the old aluminum wire until it was all out and the new copper wire was in my hand. In this way, I worked my way around the house, and have no aluminum left.
It took a lot of weekends to do and wasn't a task I looked forward to, but like all things once you get finished and look back, it wasn't that bad. I saved many thousands, avoided a negotiation at resell time, and I have peace of mind now as well.
Go the whole way. The pig tails are a band aid.