How to wire GFCI outlet to aluminum wiring?
All no-ox joint compounds are not equal. Penetrox A (mfgr Burndy) is non-flammable grease. 35 years ago I pig-tailed our aluminum wiring with No-Al-Ox and Scotchlok twist on connectors. No-Al-Ox I later found out (and confirmed myself) is flammable. I'm in the slow and gradual process of redoing the pigtails with AlumiConn connectors which are pre-packed with anti-oxidant grease. However, none of my old  connections with No-Al-Ox has shown any evidence of heating or failure. 

Unfortunately AlumniConns are not always available except by order. They come in 2-port and 3-port. In some cases the 2-port might be necessary to be able to fit a bulky device and all the connections and wires into the box. Also use #14 wire for the pig-tails if the circuit is 15-A because it folds and fits much easier than the #12 required for 20-A circuits.

The instructions for tightening the screws on the AlumiConn connectors are to use a torque screwdriver (10 in-lb for #12 AL and 15 in-lb for #10 AL and for #14 and #12 CU). There used to be alternative instructions on number of turns after contact with the wire, but I haven't found that lately.