The working part of Coca Cola is the carbon dioxide in the drink, in other words any soda pop will do. May I suggest you use one with a minimal sugar contents instead? I know CO2 reacts with Iron rust (Fe2O3) but I am nut sure if it works with Aluminium oxide. The CO2 in the coke makes it a (very light) acid that binds (very slowly) with the Fe2O3. You may find that vinegar works faster.
I would try to soak it in WD40 for several hours (or even a day). Put it in a bowl and cover it to minimize evaporation. If that does not work try heating and cooling it. The expansion may just free the bolt from the Aluminium. If that fails try pliers, a vice and a little persuasion.